I use a similar setup, but I drill my holes in the lid, silicone both sides, and put an aquarium air pump to one of the nozzles. Second nozzle goes into the water and out to the enclosure. Put it on a timer and refill when it needs it.
Only the top is open to airflow? If you read any care sheets online, 99% say AT LEAST two sides of the enclosure should be screen. Beyond that I'd be concerned that the cham could escape through the bars, or worse, get stuck in them. A digital thermometer should also be something you buy LONG...