Add the tomato sauce, broth, black beans and tomatoes. Allow the mixture to simmer until the sauce thickens.
Sprinkle the cheese over the top, cover with a tight fitting lid (or a large piece of aluminum foil) and remove from the heat. After about a minute or two, remove the lid and top with green onion and lettuce. Serve the skillet as a dip, use it as a taco or burrito filling, or as a nacho topping. Garnish with avocado, sour cream or cilantro, if desired.
Notes
*I used ground beef for this recipe, but ground chicken (or even turkey) would be just as delicious!