Your situation is a classic amongst so many GSD puppy owners....including me.
I'll bet if you search the puppy forums you will find countless threads which discuss your current situation regarding the nipping.
As far as the " ...she keeps waking up every couple hours at night...." situation, I'd take a stab at tiring her out more before her evening snooze. If she's still really young and doing the on/off switch thing, I'd try and keep the on switch activated a bit longer. It seemed like short phase with the GSD pups I've had but I distinctly remember the days of....going a hundred miles an hour and then a half hour later they are fast asleep in some of the most awkward and uncomfortable positions.
However, nothing wrong with a pup that loves to play.....she just hasn't figured out your timetable yet...I guess.