The heat is what the problem is. What feels lukewarm to us can be scalding to a chameleon. When I got my beardie and he needed a bath, I started getting temps on my water and was shocked to learn that my cold water is in the 70’s! 90 degrees barely feels warm. So if what you are gauging as hot to you, it would be torture for a chameleon. Also, yes, as has been said heat plus humidity increases risks for respiratory infection. However, you are correct in that using humidity is a good way to help hydrate chameleons, but there is a better and safer way to do it. It’s called naturalistic hydration and if you head over to chameleon academy I’m sure you can find at least one podcast on it and lots of info. I did find a few videos on it and adding a couple below. This is the basic idea of it. You first need to ensure that you have a decent temp drop at night to below at least 68-70. Then you run a
cool mist humidifier and boost the humidity all the way during the night. This simulates the hydration that is provided by fog in nature.
Hornworms and silkworms are wonderfully hydrating food items too.
https://www.youtube.com/live/HwdehHLcSzM?si=FzvCweoNh_Icx-hT