Saute first four ingredients of sauce, pour off excess liquid. Add remaining sauce ingredients. Cook all over medium heat for 30 minutes. Butter/grease a 9x13 casserole dish. Pour 1/3 sauce over bottom. Cover with 2 tortillas. Cover tortillas with 1/3 sour cream, spread evenly. Sprinkle 1/3 cheese over sour cream. Repeat steps until 3 layers are made.
Bake at 350 until all ingredients are warmed/melted, about 45 minutes.