In large bowl combine cheese, onion and chicken. Fry tortillas in large skillet, one at a time in hot oil for 15 seconds each side (spread newspaper or paper sack for draining tortillas as you cook them.) Spoon chicken mixture on all twelve tortillas, roll up and place seam side down in large baking pan.
In saucepan, melt butter, blend in flour, add chicken broth, and cook until mixture thickens and bubbles. Stir in sour cream and green chilies. Cook until heated through, but DO NOT BOIL. Pour sauce over tortillas and bake at 425 degrees for 20 to 25 minutes. Serve piping hot.
