I mist during the day. To be exact I have a misting 15 minutes after lights come on and then another one around 4pm and 6:15pm prior to lights off. My cham will not drink consistently from a dripper and if you are misting at night you are hoping for hydration through breathing in the cold humidity. And then drinking from a dripper during the day.
I also live in a very dry climate so I have to mist during the day to increase my daytime humidity to where it needs to be.
I think this is one of those husbandry practices that really needs to be fitted to the chameleon.