In a medium soup pot, combine all ingredients; cook over medium heat until soup is heated through, about 15 minutes. Stir several times during cooking so that the beans don't stick to the bottom of the pan and burn. The soup may be served with cornbread, crackers, etc. Leftovers may be placed in freezer containers or frozen and placed in plastic freezer bags.
Note: If you don't care for large chunks of tomato in your soup, try this: Empty the 30-ounce can of chili beans into the soup pot, then rinse the can with water. Place the diced tomatoes into the empty chili bean can and cut the tomatoes to desired size with stainless steel kitchen shears.