let the moths mate and lay eggs. (You can then raise your own hornworms when the lavae hatch and only need to buy the hornworm food from the usual suppliers).
I expect if the worms are OK to use as feeders, the pupae and moths will be too, as the moths get rid of their intestines and stomach contents prior to pupating (like silkworms do), so there are not likely to be any toxins (from the stuff they've eaten) inside the pupae or moths' bodies.
Your beardie will probably enjoy catching the moths in it's enclosure too.