How long have you had him? I agree, it could be because he's declawed. His only means of defense now is to bite. If you just adopted him it may take him awhile to completely trust you.
Has he broken skin? If not, then I would say he's not trying to cause harm and may be play biting. If he was taken from his mom and siblings early, he was never taught what is and isn't appropriate behavior.
If he's running across the room and nipping, this may be his way of playing. Trying using a firm "NO!" and placing a finger in front of his nose, but do NOT touch his nose. You just want him to learn that NO means to stop his forward momentum. Then use a distraction, like a wand with feathers or string, to get his attention off of you. It may take a while but you will need to be consistent. There are also products like Bitter Apple that you can spray on your skin to help deter him.
My current foster boy, Max, also likes to give 'love bites'. His also can be hard, enough to leave an impression but not break the skin, but it is definitely not out of aggression. He is just a very mouthy and vocal (growls) Meezer who always lets you know what's on his mind. I'm still working with him on this and hopefully he will eventually get it.