My 2 year old son is a great sleeper, but he goes through phases where he will fight us at naptime and bedtime. You just have to be consistent, keep telling him it's time to go to sleep, keep returning him to his bed. I also will tell him something fun we'll do when he wakes up, but only if he takes a nap. I find that sometimes I just have to leave the room for a few minutes, especially if I start getting frustrated. I just tell him, "mommy's going now, good night," and I leave. Usually I wait a few minutes, (and he will sit there and cry or yell) then I go back and tuck him in, give him a kiss and tell him again that it's time to sleep. The few minutes apart seems to do it. Just try to stay calm, you know he'll sleep eventually! And don't give up on naps, they still need them at this age, and we need the quiet time!