My cham is not a superworm fan at all. He will eventually eat them, but only under duress. Your cham may just not be a superworm kind of guy.
If you have not done a lot of handfeeding, your cham may be nervous to take a superworm from you especially as it's a novel food for him. Try hand feeding crickets instead, to make sure he will take those from you. You can also try the "sandwich" method: offer him a cricket from your hand, then follow it up with superworm. If he takes that, follow it up with another cricket. You're basically teaching him that superworms are as good to eat as crickets! It's the only way I got my guy to eat them. Note: if you don't follow the yucky superworm up with a tasty cricket, it's possible your cham will start to refuse to take food from you at all.
You could also try a different feeder; you can get tiny silkworms or hornworms and try those. My cham likes both. His absolute favourite, though, is anything that flies. I pupate blue bottle fly maggots, waxworms, silkworms, and black soldier fly larvae (aka phoenix worms aka calci-worms) and he goes nuts for the adult fluttering forms.