First, you'll need to create a GitHub OAuth app for your organisation.
Creating a GitHub OAuth app
Section titled “Creating a GitHub OAuth app”From GitHub, click on your profile picture and chose "Settings":

Then "Developer settings" from the left-hand menu:

Then "OAuth Apps":

And create a new OAuth app:

Give it a name, and a homepage URL. The authorization callback is the important bit. It needs to be in this form:
[your-nx-cloud-url]/auth-callback
# for examplehttps://my.nx-enterprise.url:8080/auth-callback
Once you create, keep a note of the Client ID:

And then generate a new client secret, and save it somewhere secure (we'll use it in a bit):

Configure Nx Cloud Installation
Section titled “Configure Nx Cloud Installation”Contact your developer productivity engineer to connect your Nx Cloud instance to the newly created GitHub OAuth app.