diff --git a/README.md b/README.md
index 185ddfb..55def79 100644
--- a/README.md
+++ b/README.md
@@ -72,6 +72,31 @@ make down
 
 See `values.yaml` for all configuration options. The chart wraps the [JupyterHub Helm chart](https://z2jh.jupyter.org/) - all `jupyterhub.*` values are passed through.
 
+### Nebi Registries
+
+Admins can provision OCI registries for every user's nebi instance via
+`nebi.registries`. Only public (unauthenticated) registries are supported;
+entries carry no credentials:
+
+```yaml
+nebi:
+  registries:
+    - name: acme-registry
+      url: registry.acme.com
+      namespace: acme-envs
+      default: true
+```
+
+Each entry follows nebi's own `registries.entries` schema (`name`, `url`,
+`namespace`, `default`) and is rendered into a ConfigMap mounted into user
+pods, so entries are locked in the UI rather than editable per-user.
+
+Set `nebi.seedDefaultRegistry: false` to remove the built-in
+`quay.io/nebari_environments` registry that nebi seeds by default.
+
+Both settings only take effect for user servers started after the hub pod
+restarts, since the mount wiring lives in the hub ConfigMap.
+
 ## Shared Storage
 
 Per-group shared directories (`/shared/<group>` in every user pod) need a
diff --git a/config/jupyterhub/01-spawner.py b/config/jupyterhub/01-spawner.py
index 6a1e5bf..79ee718 100644
--- a/config/jupyterhub/01-spawner.py
+++ b/config/jupyterhub/01-spawner.py
@@ -70,6 +70,29 @@
     },
 ]
 
+# ---------------------------------------------------------------------------
+# Admin-provisioned nebi config (OCI registries, default-registry seed flag).
+# Helm renders the deployer's `nebi.registries` / `nebi.seedDefaultRegistry`
+# values into a ConfigMap and substitutes its name below; the placeholder
+# stays literal (and is skipped) when the deployer customizes neither value.
+# nebi searches /etc/nebi/config.yaml at boot, so mounting is all it takes.
+# ---------------------------------------------------------------------------
+_NEBI_CONFIG_CM = "__NEBI_CONFIG_CM__"
+if _NEBI_CONFIG_CM and not _NEBI_CONFIG_CM.startswith("__"):
+    c.KubeSpawner.volumes.append(
+        {
+            "name": "nebi-config",
+            "configMap": {"name": _NEBI_CONFIG_CM},
+        }
+    )
+    c.KubeSpawner.volume_mounts.append(
+        {
+            "name": "nebi-config",
+            "mountPath": "/etc/nebi/config.yaml",
+            "subPath": "config.yaml",
+        }
+    )
+
 c.KubeSpawner.notebook_dir = "/home/jovyan"
 c.KubeSpawner.working_dir = "/home/jovyan"
 
@@ -259,6 +282,16 @@ def _setup_trust_bundle(spawner):
 
 env["NEBI_STORAGE_WORKSPACES_DIR"] = "/var/lib/nebi/workspaces"
 
+# nebi's local-mode netguard only accepts loopback Origin headers by default.
+# Browsers send the hub's public origin on CORS-mode asset requests (the SPA
+# bundle is emitted as <script type="module" crossorigin>), which blanked the
+# Nebi tile (nebari-dev/nebi#489). Allow the hub origin explicitly; the env
+# var reaches nebi because jupyter-server-proxy children inherit the pod
+# environment. Older nebi builds without server.allowed_origins ignore it.
+_hub_external_host = get_chart_config("external-url")
+if _hub_external_host:
+    env["NEBI_SERVER_ALLOWED_ORIGINS"] = f"https://{_hub_external_host}"
+
 c.KubeSpawner.environment = env
 
 
diff --git a/templates/_helpers.tpl b/templates/_helpers.tpl
index abc9bb8..2185393 100644
--- a/templates/_helpers.tpl
+++ b/templates/_helpers.tpl
@@ -49,6 +49,17 @@ Singleuser config ConfigMap name
 {{- printf "%s-singleuser-config" (include "nebari-data-science-pack.name" .) -}}
 {{- end }}
 
+{{/*
+Nebi config ConfigMap name (admin-provisioned registries). Returns "" when
+the deployer customizes neither nebi.registries nor nebi.seedDefaultRegistry,
+so consumers can use emptiness as the single enable/disable signal.
+*/}}
+{{- define "nebari-data-science-pack.nebi-config" -}}
+{{- if or .Values.nebi.registries (not .Values.nebi.seedDefaultRegistry) -}}
+{{- printf "%s-nebi-config" (include "nebari-data-science-pack.name" .) -}}
+{{- end -}}
+{{- end }}
+
 {{/*
 Selector labels
 */}}
diff --git a/templates/hub-config.yaml b/templates/hub-config.yaml
index 6ec8cbd..721a6b0 100644
--- a/templates/hub-config.yaml
+++ b/templates/hub-config.yaml
@@ -16,6 +16,7 @@ metadata:
 {{- if $hubHost }}
 {{- $gatewayAuthPy = $gatewayAuthPy | replace "__CHART_OAUTH_CALLBACK_URL__" (printf "https://%s/hub/oauth_callback" $hubHost) | replace "__CHART_OAUTH_EXTERNAL_URL__" (printf "https://%s/" $hubHost) -}}
 {{- end }}
+{{- $nebiConfigCM := include "nebari-data-science-pack.nebi-config" . }}
 data:
   # ---------------------------------------------------------------------------
   # 00-chart-derived.py — Helm-rendered defaults for every `custom.*` URL /
@@ -74,7 +75,7 @@ data:
   00-gateway-auth.py: |
 {{ $gatewayAuthPy | indent 4 }}
   01-spawner.py: |
-{{ .Files.Get "config/jupyterhub/01-spawner.py" | replace "__SINGLEUSER_CONFIG_CM__" (include "nebari-data-science-pack.singleuser-config" .) | indent 4 }}
+{{ .Files.Get "config/jupyterhub/01-spawner.py" | replace "__SINGLEUSER_CONFIG_CM__" (include "nebari-data-science-pack.singleuser-config" .) | replace "__NEBI_CONFIG_CM__" $nebiConfigCM | indent 4 }}
   02-jhub-apps.py: |
 {{ .Files.Get "config/jupyterhub/02-jhub-apps.py" | indent 4 }}
   03-nebi-envs.py: |
diff --git a/templates/singleuser-nebi-config.yaml b/templates/singleuser-nebi-config.yaml
new file mode 100644
index 0000000..1548da8
--- /dev/null
+++ b/templates/singleuser-nebi-config.yaml
@@ -0,0 +1,23 @@
+{{- /*
+  Nebi config for singleuser pods: admin-provisioned OCI registries and the
+  default-registry seed flag. Rendered only when the deployer customizes
+  either value; mounted by 01-spawner.py at /etc/nebi/config.yaml, a path
+  nebi searches at boot. A plain ConfigMap: entries are public registry
+  pointers only, nebi does not accept credentials here.
+*/}}
+{{- if include "nebari-data-science-pack.nebi-config" . }}
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {{ include "nebari-data-science-pack.nebi-config" . }}
+  labels:
+    {{- include "nebari-data-science-pack.labels" . | nindent 4 }}
+data:
+  config.yaml: |
+    registries:
+      seed_default: {{ .Values.nebi.seedDefaultRegistry }}
+      {{- with .Values.nebi.registries }}
+      entries:
+        {{- toYaml . | nindent 8 }}
+      {{- end }}
+{{- end }}
diff --git a/tests/unit/test_spawner_nebi_config.py b/tests/unit/test_spawner_nebi_config.py
new file mode 100644
index 0000000..42f66bf
--- /dev/null
+++ b/tests/unit/test_spawner_nebi_config.py
@@ -0,0 +1,108 @@
+"""Tests for the nebi-config ConfigMap mount wiring in `01-spawner.py`.
+
+Helm substitutes __NEBI_CONFIG_CM__ with the ConfigMap name when the
+deployer sets `nebi.registries` or disables `nebi.seedDefaultRegistry`,
+and with "" otherwise. The spawner must add the /etc/nebi/config.yaml
+mount only when a real name was substituted.
+"""
+
+from __future__ import annotations
+
+import importlib.util
+import sys
+import types
+from pathlib import Path
+
+_z2jh = types.ModuleType("z2jh")
+_z2jh.get_config = lambda key, default=None: default
+sys.modules.setdefault("z2jh", _z2jh)
+
+from conftest import CONFIG_DIR, FakeConfig, load_config_module  # noqa: E402
+
+
+def _load_spawner_with_configmap(tmp_path: Path, c: FakeConfig, cm_name: str):
+    """Exec 01-spawner.py with the Helm placeholder substituted."""
+    source = (CONFIG_DIR / "01-spawner.py").read_text()
+    rendered = source.replace("__NEBI_CONFIG_CM__", cm_name)
+    path = tmp_path / "01-spawner-rendered.py"
+    path.write_text(rendered)
+
+    spec = importlib.util.spec_from_file_location("_spawner_rendered", path)
+    module = importlib.util.module_from_spec(spec)
+    module.__dict__["c"] = c
+    module.__dict__["get_chart_config"] = lambda key, default="": default
+    spec.loader.exec_module(module)
+
+
+def _nebi_volume(c: FakeConfig):
+    return next(
+        (v for v in c.KubeSpawner.volumes if v.get("name") == "nebi-config"), None
+    )
+
+
+def _nebi_mount(c: FakeConfig):
+    return next(
+        (m for m in c.KubeSpawner.volume_mounts if m.get("name") == "nebi-config"),
+        None,
+    )
+
+
+def test_no_mount_when_placeholder_unrendered():
+    """Raw source (placeholder intact) must not add the mount. This is
+    what unit tests and a template-render failure would see."""
+    c = FakeConfig()
+    load_config_module("01-spawner.py", inject_c=c)
+    assert _nebi_volume(c) is None
+    assert _nebi_mount(c) is None
+
+
+def test_no_mount_when_configmap_name_empty(tmp_path):
+    """Helm substitutes "" when the deployer customizes nothing."""
+    c = FakeConfig()
+    _load_spawner_with_configmap(tmp_path, c, "")
+    assert _nebi_volume(c) is None
+    assert _nebi_mount(c) is None
+
+
+def test_mount_added_when_configmap_rendered(tmp_path):
+    c = FakeConfig()
+    _load_spawner_with_configmap(tmp_path, c, "my-pack-nebi-config")
+
+    volume = _nebi_volume(c)
+    assert volume is not None, "nebi-config volume missing"
+    assert volume["configMap"]["name"] == "my-pack-nebi-config"
+
+    mount = _nebi_mount(c)
+    assert mount is not None, "nebi-config volume_mount missing"
+    assert mount["mountPath"] == "/etc/nebi/config.yaml"
+    assert mount["subPath"] == "config.yaml"
+
+
+def _load_spawner_with_chart_config(c: FakeConfig, chart_values: dict):
+    """Exec raw 01-spawner.py with a custom get_chart_config stub."""
+    path = CONFIG_DIR / "01-spawner.py"
+    spec = importlib.util.spec_from_file_location("_spawner_chartcfg", path)
+    module = importlib.util.module_from_spec(spec)
+    module.__dict__["c"] = c
+    module.__dict__["get_chart_config"] = (
+        lambda key, default="": chart_values.get(key, default)
+    )
+    spec.loader.exec_module(module)
+
+
+def test_allowed_origins_env_set_from_hub_host():
+    """The hub public origin must be allowlisted for nebi netguard
+    (nebari-dev/nebi#489), or browsers get 403 on the SPA asset bundle."""
+    c = FakeConfig()
+    _load_spawner_with_chart_config(c, {"external-url": "hub.example.com"})
+    assert (
+        c.KubeSpawner.environment["NEBI_SERVER_ALLOWED_ORIGINS"]
+        == "https://hub.example.com"
+    )
+
+
+def test_allowed_origins_env_absent_without_hub_host():
+    """No derivable hub host (plain kind deploy): do not set an empty origin."""
+    c = FakeConfig()
+    _load_spawner_with_chart_config(c, {})
+    assert "NEBI_SERVER_ALLOWED_ORIGINS" not in c.KubeSpawner.environment
diff --git a/values.yaml b/values.yaml
index 8b6929d..bdfdfa7 100644
--- a/values.yaml
+++ b/values.yaml
@@ -247,6 +247,23 @@ nebi:
   # Port the Nebi server listens on (used in hub -> nebi NetworkPolicy
   # egress rule).
   port: 8460
+  # Seed nebi's built-in default registry (quay.io/nebari_environments) in
+  # each user's per-pod nebi instance. Set false to remove it everywhere.
+  seedDefaultRegistry: true
+  # Admin-provisioned OCI registries for every user's nebi instance.
+  # Public (unauthenticated) registries only; entries carry no credentials.
+  # Rendered into a ConfigMap mounted at /etc/nebi/config.yaml in user pods
+  # (which nebi searches at boot). Each entry uses nebi's own
+  # `registries.entries` schema: name, url, namespace, default.
+  # Changes to this value (and to seedDefaultRegistry above) take effect
+  # only for user servers started after the hub pod restarts, since the
+  # mount wiring lives in the hub ConfigMap (01-spawner.py).
+  registries: []
+  # registries:
+  #   - name: acme-registry
+  #     url: registry.acme.com
+  #     namespace: acme-envs
+  #     default: true
 
 # Helm Job that one-shots Keycloak realm config for role-gated shared
 # mounts. Runs as a post-install / post-upgrade