He's just new. If you only just got him, he's scared and stressed out. Imagine being super tiny, and then having a giant come over you and grab you with their hands. You'd be scared too! A bite is just his defense mechanism.
The best thing to do is work on taming him. If you're worried he'll bite (and I know the feeling, bites hurt!) wear some thick gardening gloves. Start off with putting toilet paper that's scented like you (I put mine in my bra) around his cage so he gets used to your scent. Talk to him softly. When you place your hand in his cage, place it down palm up and put a treat in it. Since he's a dwarf (from a pet store it's unlikely he's pure winter white, he's likely a hybrid) I would use some veggies or a sunflower seed. He will begin to associate your hand with food and treats and be less likely to attack you if enter "his territory".
Also, if he has a nice large house he might be less aggressive. What kind of cage do you have, and how big is it? I give my hamsters at least a 20gal long tank which gives them 360sq in of room to run around.
Just remember hamsters will be hamsters. Dwarfs tend to be nippy but patience and confidence will help.
I hope my reply was helpful. I have two Russian Campbell's myself and while they weren't super nippy, I still had to tame them. My Syrian is definitely nippy and is proving harder to tame.