Hello and welcome! A veiled chameleon should get phosphorus free calcium WITHOUT D3 dusted on each feeding. The multivitamins they need 2x a month and they need a D3 supplement 2x a month. I use Repashy LoD which is a multivitamin and the D3 in one. I use this specific supplement on the 1st and 15th of every month
It sounds like you may have just gotten your chameleon. Would you be interested in doing a full husbandry review? There is a lot of bad information out there about how to care for chameleons so it can be super helpful.