The next major update Google will now Roll out for Supported Nexus Devices will be Android 7.0 Nougat, But seems A lucky user already got it!
The Update was actually for Googlers, but this reddit user ( brianmoyano ) luckily Got it. The update he got is of 49.5 MB.
This might be the stable release of Android 7.0 Nougat for Nexus 6P as the user is claiming that the beta icon it's no longer available in the notification menu.
source - reddit