My dogs are pretty spoiled I guess you can say, they have plenty of chew toys and they usually are happy with those but all of a sudden they started chewing my wall and I don't know how to stop it.

Mostly the same was as other things. Keep them in sight, use closed doors or gates to keep them the same room as you. When you see one starting to chew on the wall, give it a sharp ''Ah, ah, ah!'' and offer it a chew toy. Praise it if it takes the toy. It may take a while, but they should give up sooner or later. When you can't watch them, crate them.