Preheat oven to 350 degreese. In skillet, cook onions in oil until tender. Add seasonings, soup and sour cream. Heat mixture until it's smooth aned warm, then add chicken. Oil a 9x13 pan. Cover bottom with torn up oiled tortillas. add half of the chicken mixture. Add another layer of tortillas and cover with remaining filling, then top with cheese.
Bake at 350 degrees for 15 minutes or until hot and bubbly.