Lay the chuck roast into the bottom of a slow cooker with a tight-fitting lid. Sprinkle the taco seasoning mix over the beef. Pour the green salsa over the beef, followed by the beef broth.
Cook on Low for 4 hours. Add more beef broth if needed. Remove the beef from the slow cooker and shred with two forks. Return the shredded beef to the slow cooker; mix with the liquid. Serve hot.
