The face of the no-nap boy

Here's Aden after 3 hours of being in his bed, wide awake the entire time. Since he turned 2, he would go through periods of not napping. He would just stay in his bed and talk and no matter how tired he is, he just refuses to give in to sleep. It always worries me that he is starting to give up his nap, but then, he'll start napping again like normal. So every day, I put him in his bed and doesn't let him out of it until either he's napped or 3 hours has gone by (he usually naps for 3 hours). Luckily, he never cries or throws a fit, he just hangs there until his time is up.