What type of chameleon? Check the care sheets for the recommended humidity levels and experiment with different times. Some chameleons will actively drink while the misting is going on, but others (like mine

) will run for cover. Just for a starting point, I mist about 4 - 5 times a day for my veiled. Each session is for 30 - 45 seconds. I don't mist late in the day so the enclosure dries out before lights out.