Thanks so much for replying.
From what I was told he was in a too small cage with too many other pigs, and a ceramic bowl was overturned onto his back right leg. I don't think he was taken to a vet at the time. Since I've received him, he has seen a vet and I was told that his bone was most likely broken at the time, and since it was essentially neglected, it healed, but not exactly correctly. She told me that she really doesn't think its causing him pain anymore. So right now, his right leg/foot juts out a little ackwardly. He uses it, and can run like a madman when he's out of his cage and feeling frisky. I really don't think his leg has anything to do with his liking to nip though.
I truly don't think Bruce Lee is a full fledged breed, but he's awesome just the same. He's left side is almost completely chesnut brown while the other half is almost completely white, but its vice versa on the fur around his face. He's short haired with uber-soft but scruffy fur. He's not exactly an affectionate pig, he gets really loud and bossy when he thinks you might be keeping food from him. But he's very curious and wants to know what I'm doing at all times. Its nice having him run around on the bedroom floor with what I call "supervised play time" I don't know his whole history, but I think he was probably a victim of parents who give their kids pets without analyzing the actual care that the pet is going to need.
Thanks for your suggestions.