Layered Enchilada Bake
PREHEAT oven to 400ºF. Brown meat with onions in large skillet on medium-high heat; drain. Add salsa, beans, dressing and seasoning mix; mix well.
ARRANGE 3 of the tortillas in single layer on bottom of 13x9-inch baking dish; cover with layers of half each of the meat mixture, sour cream and cheese. Repeat all layers. Cover with foil.
BAKE, covered, 30 min. Remove foil. Bake an additional 10 min. or until casserole is heated through and cheese is melted. Let stand 5 min. before cutting to serve.