I was told by an entomologist at the zoo that it was not good to use oatmeal.
Although I have not raised superworms for my chameleon, I have had a colony of them living/breeding in my box turtle cage for several years. They eat the same greens and veggies that I list in my chameleon gutload and a bit of fruit too. I provide them with some rotting wood (someone told me this was a good thing to do for them) and there are areas of the turtle "table" substrate that are wet and others where they are dry so they have a choice of moisture levels to select to live in.