1 1/2 pound beef chuck roast 1 medium onion, sliced 1 cup water 1 package (1.25 ounce size) taco seasoning mix 1 bottle (16 ounce size) taco sauce 1 can (7 ounce size) chopped green chiles 1 package (12-count size) taco shells ***Taco Toppings*** shredded lettuce chopped tomato shredded Mild Cheddar cheese or Monterey Jack cheese sour cream
Place beef and onion in slow cooker. Combine water and seasoning mix in small bowl. Pour over beef and onion. Cook on LOW for 6-8 hours or till tender. Remove meat to cutting board; shred beef with two forks. Place beef in large bowl.
Stir in taco sauce and chiles. Fill warmed taco shells with beef mixture. Top with toppings (lettuce, tomato, cheese and sour cream).