docs(nextjs): adding workers builds env secret requirement

Author: yomna-shousha

src/content/docs/workers/framework-guides/web-apps/nextjs.mdx

@@ -102,6 +102,16 @@ Most Next.js features are supported by the Cloudflare OpenNext adapter:
 
    <PackageManagers type="run" args="deploy" />
 
+    :::note
+    [**Workers Builds**](/workers/ci-cd/builds/) requires you to configure environment variables in the ["Build Variables and secrets"](/workers/ci-cd/builds/configuration/#:~:text=Build%20variables%20and%20secrets) section. 
+
+
+    This ensures the Next build has the necessary access to both public `NEXT_PUBLC...` variables and [non-`NEXT_PUBLIC_...`](https://nextjs.org/docs/pages/guides/environment-variables#bundling-environment-variables-for-the-browser), which are essential for tasks like inlining and building SSG pages.
+
+
+    Learn more in the [OpenNext environment variable guide](https://opennext.js.org/cloudflare/howtos/env-vars#workers-builds)
+    :::
+
 </Steps>
 
 ## Deploy an existing Next.js project on Workers
@@ -192,4 +202,15 @@ You can convert an existing Next.js application to run on Cloudflare
 
     <PackageManagers type="run" args="deploy" />
 
+    :::note
+    [**Workers Builds**](/workers/ci-cd/builds/) requires you to configure environment variables in the ["Build Variables and secrets"](/workers/ci-cd/builds/configuration/#:~:text=Build%20variables%20and%20secrets) section. 
+
+
+    This ensures the Next build has the necessary access to both public `NEXT_PUBLC...` variables and [non-`NEXT_PUBLIC_...`](https://nextjs.org/docs/pages/guides/environment-variables#bundling-environment-variables-for-the-browser), which are essential for tasks like inlining and building SSG pages.
+
+
+    Learn more in the [OpenNext environment variable guide](https://opennext.js.org/cloudflare/howtos/env-vars#workers-builds)
+    :::
+
+
 </Steps>