I would suggest buying (or making your own) shooting gallery style feeding station. I’ve made my own versions of it a few times from various plastic food containers. I can’t recall if they came from a frozen meal or take out, but I washed it very well before making. You could probably use any plastic food containers. Leaving about 1/4 x 1/3 of the bottom intact, cut a big enough hole for your cham to easily stick its head into. I sand down the cut sharp edges and then apply a scant thread of hot glue to make sure it’s dull enough. I kind of smear just the smallest thread of hot glue for better adhesion. If you run a nice line of it, it can easily come off. Some dull the edges with a lighter. I had poor success with that method. To stick it to the inside of the screen door, I use push pins stuck thru from the inside and then I found pencil eraser material adequate to secure by placing on the sharp points on the outside. You could probably use thin wire to secure it and not have to deal with push pins and erasers. lol It stays in place and with the exception of bsfl and wax worms, it helps prevent feeders from escaping easily. There are all different variations out there to buy, especially on Etsy. I hope I’ve helped a bit.