I can only suggest not allowing him onto bare hands until he`s used to actually being socialised. Each day when he`s fully awake and not tired or disturbed, you could use a tool like a pocket hammock or a towel to let him wander around on your knee, but without him being allowed to nip. Hamsters need conditioning into realising that a hand or a scoop isn`t a bad thing, but something to be rewarded for.
YouTube has some good (and some not so good) tutorials on Chinese and Russian dwarf hamster taming videos. But it`s mostly building each day on the positives and taking small steps, rather than concentrating on the negatives. I don`t personally feel that hamsters that bite are `bad`, they are just misunderstood and we would probably be the same if we found ourselves in a situation we were not comfortable with. It`s a bite and flight response in many ways. Keeping your hand flat rather than curved over might also help. But as I suggested earlier, I would use a tool for him to voluntarily walk into and be rewarded for it.
Always take a step back if things don`t go well. This means he`s not ready to move on yet. Only advance steps once he`s actually comfortable even with walking into or onto something.