Have you consulted a vet about possible oxytocin injections? If she cant lay her eggs, and oxytocin doesnt help, she will need to have them surgically removed. As for force feeding, if she absolutely needs it (like if her eggs are not yet fully developed) then I would use mainly mashed up insects that are well gutloaded and some vitamins/calcium or whatever your chameleon experienced vet recommends. Now, is her tank what you are using for laying? I cant tell how deep the laying medium is, but it needs to be at least 12 inches deep and 12 inches wide. A good idea would be to use a large plastic trash can and fill it with 12+ inches of damp soil and/or sand. Then place a plant and some vines in the bin so that she has the opportunity to climb if she can and is still able to dig in a suitable area. Also make a "starter" hole in the substrate so that she can use it if she needs to. Try making it several inches deep, big enough for her to climb into, and at an angle. Be absolutely certain that if she starts digging she does not see you. If she is forced to abandon the hole, what little strength she had might have been completely used up.