I can speak from personal experience here in saying that flashing and rooting Android devices is always a little bit tricky for Mac users. The majority of instructions found on XDA or RootzWiki are written for Windows users, and most toolkits are as well. Today however, things have gotten a bit easier for owners of Macs and Nexus 7s.
These toolkits are a bit light on the features so far, but you can root/unroot, unlock/relock the bootloader and install ClockworkMod Recovery with these scripts. A fantastic start and it will sure to be welcome from Mac users. Head over to XDA at the link below for downloads and a place to leave feedback if you need to.