one of my favorite subjects... here's a rant (sorry).
1st of all, that idea won't work. The misting nozzles require a very high
pressure (at least 25psi - ok, not that high, but higher than an air pump
can do). What MIGHT work, with the air pump, or any other water
pump, are those cheap, low pressure garden "misting' nozzles. Not sure
how much pressure they require, but I'm sure they'll at least spray a bit.
An air pump, or a pond pump, cannot pump water more than a couple
feet high. That means you'd have to have the water container up on the
level of the top of the cage.
Ultrafine mist nozzles require the higher pressure of a purpose built
pump. If you used a lower pressure, not-so-fine mist nozzle, you'll likely
flood the cage, and empty the water in no time. You really dont' want to
use anythign but LOW-FLOW fine mist nozzles for indoor chameleon
cages.
Even with one chameleon, a misting system is a good investment. You
spend a few hundred on the animal and setup, might as well spend some
more...
you have to be careful with the $100 systems. You cannot let it run
dry. however, having a misting system, even for one chameleon, makes
life easier. I spent most of my time with them watering them. Now, it
takes up maybe 5-10 minutes a week to fill the bucket. If you are going
to be going away, the mister healps. With water, you can leave them for
a week with no worries, without having to pay someone to care for
them.
I put mine together over the course of over 2 years, and it was a great investment.