what various larva will eat varies
Superworms and mealworms: will eat most any vegetable or fruit, but good ones include papaya, dandelion, butternut squash, carrot, and apple. A substrate
like this is also partly a gutload. Use a calcium supplement every time.
Silkworms: are gutloaded on mulberry leaves (or chow based on dried mulberry leaves), dandelion leaves, shaved carrot, organic sweet red pepper, grape leaves, etc. If you gutload with this selection, no supplementation required unless they form more than 20% of the chameleons diet in which case use a little calicum.
Hornworms: Hornworms are gutloaded on a purchased prepared "chow", sweet red or green bell peppers (organic), apple, maybe grape vine leaves (sometimes they eat these, sometimes they do not - not sure why), dandelion leaves, sweet potatoe (lightly steamed and cooled), basil, etc. A little calcium supplemetation is good. You can try making a paste (blender) from dandelion, a red bell pepper (organic), grape vine leaves, arugula, mustard greens, basil, some half-cooked sweet potatoe, some carrot, some wheat germ, a dash of spirulina and a little brewers yeast.
Solder fly maggots / calciworms / phoenixworms: soft, almost rotting veggies
Butterworms will eat soft (steamed and cooled) butternut squash, which is a good gutload for any feeder. They'll also eat thin shaved or half steamed (and cooled) carrot, and many other things. They are naturally high in calcium, and retain much of their inherent nutrients if kept cool (dormant). They do not need a calcium supplement, but a little vitamin supplement would be good now and then, especially if you use butterworms fairly often.