When you try to pet her, try petting her from behind. If you approach her head on, she may feel defensive. Make sure you praise her as you pet her from behind as it gives her a sense of security.
I also do agree with using toys. She needs to see toys as a positive play/chew toy, not your fingers. If she nips you, give a loud "yelp" and turn your back and ignore her. Also, if she mouthes your hand or fingers, put your finger a little bit down her throat (says my vet). She will think fingers=yucky, but be careful!
Hope this helps!
