You don't really want to be that kind of hypocrite do ya 'Bunk? If you're still biting your nails, she learned it from you most likely... and imitating someone she loves, respects, and admires!
Punishment is not the way! It will only make her more determined... she'll show you! Rewarding would be better... much better!
If you couldn't stop, how do you expect her to? The not biting while you're around prolly takes a lot of will power for her, and having a good chew is prolly one of the first things she does when she's out of your sight. There are people with Turret Syndrome that have learned to control it while out in public, but as soon as they're alone...
I say keep up the fear factor to a certain extent, but don't punish her! Wait until you find something she really wants that is borderline out of the question... then use that as the dangling carrot, but not the Disney trip if it has already been spoken about and promised.
This is just my $.02