Nipping and biting in puppies is a very normal thing to happen but you can't really stop the biting until the puppy is around 8 weeks old.
After the puppy turns 8 weeks old you can train the puppy to not nip or bite at you or other people.
Some puppies may continue the biting and nipping stage until it's corrected but most puppies will grow out of the biting and chewing and nipping at 6 months of age.
So most times it just requires waiting until the puppy grows out of it.