diff --git a/packages/nuxt/src/core/nuxt.ts b/packages/nuxt/src/core/nuxt.ts
index 6d4d62524e..20d59295dc 100644
--- a/packages/nuxt/src/core/nuxt.ts
+++ b/packages/nuxt/src/core/nuxt.ts
@@ -4,7 +4,7 @@ import ignore from 'ignore'
 import type { LoadNuxtOptions } from '@nuxt/kit'
 import { addBuildPlugin, addComponent, addPlugin, addRouteMiddleware, addServerPlugin, addVitePlugin, addWebpackPlugin, installModule, loadNuxtConfig, logger, nuxtCtx, resolveAlias, resolveFiles, resolveIgnorePatterns, resolvePath, tryResolveModule, useNitro } from '@nuxt/kit'
 import { resolvePath as _resolvePath } from 'mlly'
-import type { Nuxt, NuxtHooks, NuxtModule, NuxtOptions, RuntimeConfig } from 'nuxt/schema'
+import type { Nuxt, NuxtHooks, NuxtModule, NuxtOptions } from 'nuxt/schema'
 import type { PackageJson } from 'pkg-types'
 import { readPackageJSON, resolvePackageJSON } from 'pkg-types'
 import { hash } from 'ohash'
@@ -645,8 +645,22 @@ export async function loadNuxt (opts: LoadNuxtOptions): Promise<Nuxt> {
     options._modules.push('@nuxt/telemetry')
   }
 
-  // Ensure we share runtime config between Nuxt and Nitro
-  options.runtimeConfig = options.nitro.runtimeConfig as RuntimeConfig
+  // Ensure we share key config between Nuxt and Nitro
+  createPortalProperties(options.nitro.runtimeConfig, options, ['nitro.runtimeConfig', 'runtimeConfig'])
+  createPortalProperties(options.nitro.routeRules, options, ['nitro.routeRules', 'routeRules'])
+
+  // prevent replacement of options.nitro
+  const nitroOptions = options.nitro
+  Object.defineProperties(options, {
+    nitro: {
+      configurable: false,
+      enumerable: true,
+      get: () => nitroOptions,
+      set (value) {
+        Object.assign(nitroOptions, value)
+      },
+    },
+  })
 
   const nuxt = createNuxt(options)
 
@@ -695,3 +709,31 @@ function deduplicateArray<T = unknown> (maybeArray: T): T {
   }
   return fresh as T
 }
+
+function createPortalProperties (sourceValue: any, options: NuxtOptions, paths: string[]) {
+  let sharedValue = sourceValue
+
+  for (const path of paths) {
+    const segments = path.split('.')
+    const key = segments.pop()!
+    let parent: Record<string, any> = options
+
+    while (segments.length) {
+      const key = segments.shift()!
+      parent = parent[key] || (parent[key] = {})
+    }
+
+    delete parent[key]
+
+    Object.defineProperties(parent, {
+      [key]: {
+        configurable: false,
+        enumerable: true,
+        get: () => sharedValue,
+        set (value) {
+          sharedValue = value
+        },
+      },
+    })
+  }
+}
diff --git a/test/fixtures/basic/nuxt.config.ts b/test/fixtures/basic/nuxt.config.ts
index 08f427b2a6..320f957777 100644
--- a/test/fixtures/basic/nuxt.config.ts
+++ b/test/fixtures/basic/nuxt.config.ts
@@ -1,5 +1,6 @@
 import { addBuildPlugin, addComponent } from 'nuxt/kit'
 import type { NuxtPage } from 'nuxt/schema'
+import { defu } from 'defu'
 import { createUnplugin } from 'unplugin'
 import { withoutLeadingSlash } from 'ufo'
 
@@ -88,10 +89,17 @@ export default defineNuxtConfig({
   runtimeConfig: {
     public: {
       needsFallback: undefined,
-      testConfig: 123,
     },
   },
   modules: [
+    function (_options, nuxt) {
+      // ensure setting `runtimeConfig` also sets `nitro.runtimeConfig`
+      nuxt.options.runtimeConfig = defu(nuxt.options.runtimeConfig, {
+        public: {
+          testConfig: 123,
+        },
+      })
+    },
     function (_options, nuxt) {
       nuxt.hook('modules:done', () => {
         // @ts-expect-error not valid nuxt option