Have you tried flying bugs such as black soldier flies? You can get the larvae (and let them pupate) at many places including Petco... pricey but if all your getting is a few, its cheaper than shipping. Flying insects will entice most chams to strike. You could also get some green banana roaches. The bright green and fast movements get their attention. They are pricey and I would try the black soldier flies first.
Once your cham expands her pallet to flies, she may try some other things.