Brown meat and chopped onion in a skillet and season with salt and pepper to taste. Add soups, green chilies, enchilada sauce and milk. Line a 9x13 inch pan with 6 tortillas and top with half the meat mixture and half the cheeses. Repeat layers. Bake at 350 degrees for 40 minutes; cool slightly and cut into squares to serve. Top each square with a dab of sour cream. Serves 8. Randy Rigg