Every hamster is going to be different so if one technique doesn't work, there'll often be a different approach you can try.
The first thing to do is to work out why he's nipping. If he is territorial then sometimes this can be overcome by changing the cage but on other occasions a hamster will always be territorial in their own cage so you may need to look at interacting with your hamster outside of his cage. You can always use a mug or a toilet roll tube to get him out of his cage to transfer him to a more neutral space. It may just be that he's nipping as he's just woken up and needs time to be ready to play.
It could be that he's learnt to expect treats every time you hold him and nibbles in expectation that there's going to be something edible there waiting for him. I had a young Chinese who had got into a habit of nibbling me every time I held him so I literally had to stop giving him any treats directly from my hands or fingers. If he nipped, I just ignored it and eventually he seemed to realise that it would not only get no reaction from me but also that he wasn't going to get any treats whilst he was sat on my hands. Instead, I would always drop his seeds on to his hammock from the roof of his cage... as well as stopping the nipping, he also learnt to go up to his hammock and wait for his post-playtime treats.