I'm sorry we let this fall off our radar. Your pics are very clear and easy to see.
If it were me, I'd have vines going up to within a few (maybe 5) inches of the roof of the cage. Vertical climbing is a big thing for chameleons.
You can create good climbing vines using soft garden tie material like this:
You should be able to find it at any place with a substantial garden department.
Do you have a laying bin in there for her? I think that's essential and I don't see one in your picture.
Is the green bowl to catch water or is it acting as a feeder cup?
I think 90 degrees is pretty warm for a female. I think you can drop that down to 80-85. It might increase her desire to spend time at the top and it will help reduce the size of the egg clutches.
When you say she is sleeping "at the bottom" is she on a branch near the bottom or is she actually sleeping on the floor of the cage?
I sort of think your night time temps are too hot and that's why she's staying low. If she's actually on the bottom, that would be a different story.
Based on what I've read here, your cage temps should drop significantly at night and there is no reason for a temperature gradient at night. Don't put any heat at the top of the cage at night. The only reason to worry about night time heat is if your home gets unbearably cold at night. Like, under 50 degrees.
One thing chameleons seem to be is good sleepers. They find their spot and stay there without moving for the night.