Plants are pretty much essential because without them your cham will feel out of its element, exposed and vulnerable. As prey animals that would be extremely stressful and could cause health problems because of it. You could try live non-toxic plants so if your cham munches on them it's not a problem. I use all fake plants in my veiled's cage and he likes real greens so I have a little platform where I put fresh greens like collards, mustards, and kale. He knows where they are and expects them so he doesn't try to eat his fake plants anymore. I would try to give your cham real greens to discourage him from trying to eat the fake ones.