If you can be sure that the insects are pesticide free, they are probably ok..but know what you are feeding..certain catapillars are poisonous..fish won't work
Proceed with caution when catching insects, aside from pollution and pesticides, some are poisonous..I'd suggest ordering a starter...
There are lizards that eat fish..but most likely not chameleons, though they might try if given access..my water dragon eats fish and most monitors will as well..It's common sense..a aquatic lizard most likely will while an arboreal lizard like a chameleon will not..