DD1 is a spirited kid. She's been telling me for almost a year that she doesn't want to nap. She would try the ol' I'll-lay-in-bed-and-wait-for-a-while trick but I have a monitor in her room so I can hear her. First, I had to teach her that if she was going to sleep that she had to close her eyes, keep them closed and we worked on closing our eyes. She would squeeze them shut. Then she had to lay still not move. We talked about her body and how it fell asleep. We talked about how she may not feel like she needs a nap but her body is saying (in a silly voice) "Alila, I'm tired. Please lay down and let me rest."
I'd also go up there and tell her that she isn't leaving her room until she napped. I also told her that she didn't have to take a long nap; she only had to take a teeny tiny nap but she had to nap. She was cool with that. Obviously, I'd let her sleep as long as she needed which was always about 1.5 hours.