Sour Cream Enchiladas Casserole

We don't do Cream of Mushroom soup... big no no in Additive Avoidance cooking. This was what I came up with to compensate. It OVERcompensates. SO yummy and creamy.

4 boneless, skinless chicken breasts
4 T. butter
2 lg. mushrooms, finely diced
2 c. milk
1/3 c. flour
3 tsp. salt
1 tsp. sugar
1/2 tsp. onion powder
1 pt. sour cream

Turn oven on to 350°. Wrap chicken breasts in foil "pouch", sealing edges, and roast for 45 minutes. Remove and allow to cool. Meanwhile, saute mushrooms in butter over MED HI heat in medium saucepan. In a shaker or mason jar with lid, shake flour and milk until smooth. Add slowly to mushrooms, stirring constantly until thick and bubbly. Turn down heat and stir in salt, sugar, and sour cream. Cover and set cream sauce aside.

2 (7-oz.) cans Herdez Salsa Verde, or diced green chiles
1 med. onion, chopped finely
1 (2.25-oz.) can chopped olives
8-10 flour tortillas
1 lb. colby-jack cheese, grated

In a large mixing bowl, shred chicken breasts into bite-size strips with hands. Add salsa verde or chiles, onion, and olives. Pour cream sauce over and gently mix with large spoon. In a buttered 9 x 13 casserole dish, layer 1/2 tortillas, tearing to fit, 1/2 chicken mixture, and 1/2 cheese. Repeat layers once more. Cover and bake at 350° for 30 minutes.