Clip the nails ASAP.
Nipping is normal puppy play, i am guessing the puppy is very young? The mum will teach bite inhibition, but if the pup is taken away too young then you have to teach the pup. Do not use aversives or punishments, she is not being naughty, just being a puppy. When she nips, distract her with a toy she is allowed to bite.