Playtime stops when she nips at you. You can try saying "ouch" or "yelping", which may or may not get the point across, but ignore her for a brief time, then play can resume if she refrains from nipping. If she persists and won't leave you alone, a time out is a good idea, but need not last long. With repetition, she will discover it is much more pleasant when she does not nip.
Agree, a tired pup is usually a good pup, so if you can find an acceptable activity that wears her out, that is all to the good. Chasing and play fighting games should be avoided! That said, chasing a lure (not a person) can work well for activity. A toy or plastic bag attached to a fishing line or lunge line can work well for this.