I don't think so, but I'm not positive. But with as hard of a shell snails have I'd assume it would be WAY to hard for them to digest let alone chew. Also the snails may have a lot of parasites depending on where you found them.
Yes you can use them to feed your Cham but you have to breed them out a generation or 2 to get rid of the parasites. And you should gut load them and feed them when there young so the shells are soft. Here's a good blog that sandrachameleon has explains everything you need. Hope this helps
Yes, youll want to breed them, have them lay eggs, get rid of those adults, hatch the eggs, breed those when full grown, and then those should be safe...
Get a bin or aquarium and put some organic soil in the bottom. I mix in about 25 percent sand. Keep the soil moist. Put the largest snails in there and they will mate and lay eggs. I then remove the eggs to a new bin and discard the old snails when you're done with them. The babies will hatch in approximately two weeks. I feed mine romaine lettuce,carrots and such.