Root Nexus 7 with 4.2.2
If you want to unlock the bootloader, root and add a custom/stock ROM, then you want to use Wugs Toolkit for Nexus. (Try to borrow or use a Windows PC or laptop, its not for OS X)

Here is XDA forum link: 
http://forum.xda-developers.com/showthread.php?t=1766475

Here is the download link (this is for Windows, not OS X)
http://www.wugfresh.com/nrt/

Its pretty self explanatory, but try to read it all anyway. 

As far as I know there isn't a version for OS X

I have used this method on my 2 Nexus 7s and my friends Nexus 4 &amp; 5!!!

Happy rooting everyone!!!!