Turns out, we just needed to whip out his sleeping bag. He has been very happily napping in it all week. When he's done, he lets himself out for some quiet playtime until I come to get him. I'm thinking this will be an excellent option for vacation sleep too, since he has outgrown the Pack-n-Play, and probably a good transition to the naptime cot he'll use at preschool. The crib is still working at bedtime, so I'm not going to mess with the big boy bed switch until later.
You know what would be handy, inventors? A set of turkey pop-up timers for children. One that pops when they are ready to lose the bottle. Another when they are ready to switch to a bed. A third for when they are ready to potty train. And in the Nugget's case, one that says, "Mommy, I'm not ready to give up my nap, but I just don't want to take it in my crib anymore. What I need is a sleeping bag on the floor." Could someone please get on that?