Sara do you mean like the carrot, lima bean, green bean, and potato mix? An do you mean fresh, frozen, or canned?
I personally wouldn't use any canned items because of the sodium content and the fact that most nutrients have been striped of them. Frozen is okay I guess better than canned as for nutrients just make sure that the sodium level isn't high.
The list at beautifuldragons has carrots, canned green beans, canned lima beans all listed as a feed ocassionally and potatoes are a feed rarely item. So I'm guessing that according to that list it is okay as a treat.
So which one of your beardies likes mixed veggies?