Hello, how long have you had your hamster for?
Do you wash your hands in between offering treats? Hamsters don't rely on vision to be aware of what's going on, instead they use their noses. This however, often means that if your hand smells of food, they'll nibble at it to see. If he nibbled first, that's a sign he was exploring, and it's likely there was food residue he tasted so he tried to to take what he thought was food. I would try offering a treat, then washing your hands before attempting to handle him so that there's no smell or taste of treats still on your hands. Best wishes
