I would advise against feeding him superworms at that size. Veileds are pretty excitable eaters at times so he will probably get them down but you have to worry about them coming out. They are high in chitin. A little chitin in a chameleons' diet is great it acts in a similar fashion as fiber does to humans. To much chitin and it can have a reverse effect causing constipation.
If you are looking to mix up his diet a little bit at that size the only thing I would recommend is some meal worms. I don't really like meal worms to much as they are not very filling but it is variety. These to are high in chitin but the portion amounts would be drastically different.
On the other hand when he gets older and bigger you can utilize the meal worms for something different. They are cheap and getting them in large amounts is not a problem. Allow them to cocoon over into beetles and they are quite a tasty treat for a chameleon. Something to think about for the future, they are cheap, they are easy to maintain and I have not found a chameleon yet that does not like these beetles. I have used these as the staple feeder for awhile.
Superworm beetles are a little more hit and miss. I have two that go crazy for them. The rest will not go near them.