Freezing enchiladas after they are cooked works very well. Just cover well. You can bake a whole pan of enchiladas for a latter meal. Simply thaw the enchilada casserole and gently re-heat in the oven at 300 degrees for 30 - 45 minutes. I've not had good luck freezing un-cooked enchiladas. They can become soggy and the texture of the cheese becomes odd, affecting both taste and texture. Bake them first.