Cut roast in half and place in a 3- or 4-qt. slow cooker. Add broth. Cover and cook on low for 8-9 hours or until meat is tender. , Remove beef. When cool enough to handle, shred meat with 2 forks. Skim fat from cooking liquid; reserve 1/2 cup liquid. Return shredded beef and reserved liquid to the slow cooker. Stir in the enchilada sauce, green chilies, tomato sauce, salt, garlic powder and pepper. , Cover and cook on low for 1 hour or until heated through. Spoon beef mixture down the center of tortillas; add toppings of your choice. Roll up.