Spray inside of crock pot with cooking spray. Place roast inside crock pot. Pour the beef broth over the roast and then squeeze with fresh lime juice.
In a small bowl, whisk together chili powder, cumin, onion powder, garlic powder, salt and pepper. Sprinkle the roast with the spice mixture.
Cover with lid, and cook on Low heat 10 to 12 hours. OR cook on High heat 7 to 8 hours. Carefully remove hot roast from crock pot and transfer to a large platter. Shred meat and remove/discard any fat.
Return shredded beef to crock pot. Cover with lid and cook an additional 30 minutes. Remove beef with tongs to drain juices before serving in tortillas. Serve with desired toppings.
