You can offer a veiled the same greens (dandelions, kale, collards, endive, escarole, etc.) and veggies (carrots, squash, sweet potato, sweet red pepper, zucchini, etc.) you use to gutload/feed the insects with...and a little bit of fruit (pear, apple, melon, berries, etc.).
One of the reasons I always say to use real plants is that there is a danger of a veiled chameleon trying to ingest the fake ones...and it can lead to an impaction. The plants should be well-washed (both sides of the leaves) before using them.