The nexus devices which will get the update includes : the Nexus 6, Nexus 5X, Nexus 6P, Nexus 9, Nexus Player, Pixel C, and General Mobile 4G (Android One) will get the over-the-air update, the owners of these devices can manually check for the update.
Get Android 7.0 Via Beta Program
To get the new desert update you need to opt in for Android 7.0 Beta program, head over here to sign up to the program. Once you signed-up you will receive a little update. Later on your device will receive a update of 1.1GB.
Once you are in the Beta Program, you will receive little update. Later, your device will hit with the update of 1.1GB. If you are already in the beta and on a developer preview, most of the updates seem to be around 50MB in size.
Fresh Install by Flashing Factory Image
You can also flash fresh build of the Nougat by downloading it from here.
However we don't have the factory images for the time being. They should be appearing rather soon though.