Chew-toys are the number one cause of destructive chewing. Of all the dogs with destructive chewing problems I've worked with, at least nine out of ten were actually trained into the behavior by well meaning owners who provided them with all kinds of chew-toys.
Real bones (raw) and hard dog biscuits are fine. They are food, not toys. Nylon, rawhide, hard rubber, or plastic chew-toys have no place in raising a good dog. The proper use of toys will be the topic of a future article. For now, just don't use them.
Good luck with your training!
Neil