It's ok, they're not toxic or anything. Mealworms in and of themselves don't consist of much, they are more hard shell and fat than anything. Baby superworms are a little better, but both aren't much if you don't gutload them well and even then aren't as meaty/nutritious as a roach or cricket, for example.
The idea is just to mix it up. I'm not personally against giving superworms more often now and then, but some chameleons can end up bored of crickets and refuse to eat anything but the worms. So mixing their diet around constantly keeps them interested in everything, in my opinion.