It's legit. Although, I'm not able to test it for myself until I have the device next week. Chainfire is like the root guru on XDA.
Chainfire is the developer behind SuperSU, so you can bet that'll work
I'm glad to have found something worthwhile since I am new to the Nexus World. Still reading and learning.
I tried this method today and everything went perfect, extremely easy to do and only took about a minute.
Separate names with a comma.