Preheat oven to 350°. Brown ground beef. Add onion and chilies; simmer. Add soup and milk to hamburger mixture; stir.

Put enchilada sauce in bowl. Dip tortillas into enchilada sauce, making sure that they are completely covered on both sides, and place in 9 x 13 inch pan. Spoon out 1/3 of hamburger mixture onto the tortillas, sprinkle with cheddar cheese. Repeat these layers 3 times, adding a layer of cheese and sauce on the very top. Bake for 40 minutes.