Spray bowl of 6-to 8-quart slow coker with nonstick cooking spray. Add ketchup, mustard, vinegar, Worcestershire sauce, and garlic; whisk to combine.
Transfer brisket to cutting board. With 2 forks, shred meat. Return meat to slow-cooker bowl; stir to coat with sauce.
Serve pulled brisket with tortillas and cilantro leaves, radishes, limes, cheese, and choice of salsa.
