One of the benefits of Google's Nexus devices is that you can flash full factory images if something goes wrong. Google makes these files available for download each time a new OTA update rolls out, and the first few devices now have Nougat images. This could be just what you need to get your device back on a stock build of Android in a single step.
So far, Google only has a few images live, all of which are build NRD90M.
We'll update when new files pop up. Factory images will only work if your device has an unlocked bootloader, and the default behavior is to delete all user data. You can change that if you're flashing from a similar system, but it's risky when moving to an entirely new OS.