Update [April 13, 2017]: The April security patch is being rolled out to the Nexus 6 from AT&T. Still based on Android 7.0 build, the OTA build NBD92F is sized at around 28MB and applies the latest security patch to your device. In case you’re hoping for Android 7.1.1 update, your wait would continue for a while. The update also resolves pending issues and bugs and provides an overall performance boost through minor enhancements and tweaks.
Update [December 15, 2016]: The Nexus 6 has received the Android Nougat update, whether that be unlocked variant or the carrier-tied one. The AT&T Nexus 6 was last one to receive it on December 6, and has even see a newer update pushed out now. Verizon, Rogers, Telus, etc. have also released the Android 7.0 Nougat update for their Nexus 6 already, while in US, T-Mobile and Sprint are yet to rollout the 7.0 build to their Nexus 6 — which is ironical.
Update [October 22, 2016]: Rogers has announced the Android Nougat update release for its own Nexus 6 too, but it only says ‘coming soon’ for now. The update will be Android 7.0 naturally, as the Android 7.1 update won’t be available for the Nexus 6, unlike Nexus 5X and 6P.
Almost all Nexus 6 sets are now running Android 7.0 Nougat update, as there only few sets who are still waiting the 7.0 OTA for their sets.
One of which is the N6 at Telus, but today the carrier confirmed that it won’t be long before the days of Marshmallow are over for that set too.
Telus today announced software updates for variety of device, and of them was Nexus 6, pegged for Android Nougat update. Telus said the update is scheduled for October 24.
Recently, Verizon nexus 6 also received the Nougat update.