did you ask in the N7 forum? They might know a bit better than us...not putting you off, just trying to point you to an answer
If you want wifi tether to work on GB you need the patch from XDA.
The long and the short of it is that tethering on GB only gives you adhoc mode and to connect to most Android tablets you need infrastructure mode. The patch fixes the wifi driver and allows infrastructure mode as well.
I've downloaded several wifi drivers from xda, none seem to work on my rooted GB device. Is it time to undo everything and go ICS?
What a pain, unroot, relock, reflash ICS, unlock, reroot... Sigh...