Hand Feeding

I am having a difficult time getting my 5 Month Old veiled chameleon to feed from tongs or from my hand.

I have tried crickets, dubia roaches, hornworms, butterworms, and superworms-- He eats all of these when they are loose in his cage, or in a feeding cup.

But when I hold food in front of him, he usually just looks at me, but does not eat the food.

Is there anything I can do differently, to encourage him to hand feed (or tong feed)?

It sounds like you haven't had him for too long. It can take quite a while for any reptile to trust you. Try and start by using a handheld feeding cup especially one he's used to, or on a stick or branch similar to the one you have in your cage. You could also hold off on feeding him a while, don't be stupid about it and starve him but if you hold off just a little past his feeding time hell be more likely to accept it. Also try using his favorite food at first. He will do it eventually sometimes they won't until full grown.