Depends on the chameleon.. my female veiled will eat as many crickets as I put in the cage extremely fast. my male will eat them slowly, and only early in the morning.
My Panther eats on my hand from a cup, and let me tell you, he is one piggy!. Sometimes catches 2 or 3 at a time!. It takes him about a minute to eat 10 to 12 smalls so I break it up into multiple feedings. I've wondered Wether he would stop or just keep gorging. I've opted to not find out