Is it normal for my panther cham to start settling down about an hour before the lights go out. He ususally finds his spot and sits there and just looks around and then when the lights go out he curls his tail and goes to sleep.
Sounds good to me. If you are keeping the lights on a steady schedule he should bed down about the same time everyday. Other reasons might be that he can see outside and notice the angle of the sun coming through the window. My chams all do what you are explaining... finding a their spot to sleep before lights out.