1. In a large skillet, cook the beef over medium heat until meat is no longer pink; drain. Stir in the beans, tomatoes, Mexicorn, soup, water and chili powder. Bring to a boil. Reduce heat; simmer, uncovered, for 5 minutes.
2. Spoon beef mixture into taco shells; serve with toppings of your choice. Yield: 6 servings.