Root status: Android Nougat public build NRD90M rooted succesfully.
Although Google is yet to release Android Nougat for everyone but the update already has 4 developer previews released so far. So it isn’t really a big deal for the knowledgeable folks over at xda and other Android communities to figure out how to root Nougat update when it arrives.
Android Nougat preview release users have successfully rooted their Nexus devices with the latest SuperSU beta zip by Chainfire. Initially, when the first dev preview for Nougat arrived for supported Nexus devices, the systemless SuperSU zip didn’t work straightaway. Chainfire created a separate SuperSU zip for Nougat preview, which was later merged into SuperSU v2.74-2 that works for all Android versions.
So, basically, if you want root access on Nougat, all you gotta do is install TWRP recovery on your device and flash the latest SuperSU beta zip using TWRP install menu.
You can find detailed guide to root Android Nougat 7.0 update at the link below. Be sure to follow the guide very carefully.
Instructions → How to Root Android Nougat 7.0
We’ll sure to update this post in case rooting the next developer preview or final Android Nougat build is different from the current method.