docs: add Nuxt server API route getSession example (#863)

docs/content/docs/integrations/nuxt.mdx

@@ -68,6 +68,27 @@ const session = authClient.useSession()
 </template>
 ```
 
+### Server Usage
+
+The `api` object exported from the auth instance contains all the actions that you can perform on the server. Every endpoint made inside Better Auth is a invocable as a function. Including plugins endpoints.
+
+**Example: Getting Session on a server API route**
+
+```tsx title="server/api/example.ts"
+import { auth } from "~/lib/auth";
+
+export default defineEventHandler((event) => {
+    const session = await auth.api.getSession({
+      headers: event.headers
+    });
+
+   if(session) {
+     // access the session.session && session.user
+   }
+});
+```
+
+
 ### SSR Usage
 
 If you are using Nuxt with SSR, you can use the `useSession` function in the `setup` function of your page component and pass `useFetch` to make it work with SSR.
@@ -107,4 +128,4 @@ export default defineNuxtRouteMiddleware(async (to, from) => {
 
 - [Nuxt and Nuxt Hub example](https://github.com/atinux/nuxthub-better-auth) on GitHub.
 - [NuxtZzle is Nuxt,Drizzle ORM example](https://github.com/leamsigc/nuxt-better-auth-drizzle) on github [preview](https://nuxt-better-auth.giessen.dev/)
-- [Nuxt example](https://stackblitz.com/github/better-auth/better-auth/tree/main/examples/nuxt-example) on StackBlitz.
+- [Nuxt example](https://stackblitz.com/github/better-auth/better-auth/tree/main/examples/nuxt-example) on StackBlitz.