Don't worry - Sam's two and only knows his nose as well. He'll do more body parts for day care, but the only one we get consistently is nose.

I'd go with toys. Vary them. Something he's unfamiliar with or hasn't seen for a while. We had the same issue - and would often hand him a tube of cream from the nappy change supplies. A nose bulb aspirator thingy was great for a while (but make sure it's an unused one as it will likely go in the mouth). We just found it had to be something he wasn't used to having so it took his attention. His toys were a bit too familiar so didn't cut it.

BW