Place chicken in slow cooker. Whisk together BBQ sauce, broth, vinegar, Worcestershire, sugar, paprika, garlic, onion, salt, and pepper; pour over chicken.
Cover and cook on LOW for 6-8 hours or on HIGH for 3-4 hours until chicken is tender and easily shredded.
Remove chicken, shred with two forks, then return to slow cooker and stir to coat with sauce.
If desired, cook uncovered on HIGH for an additional 15-30 minutes to thicken sauce.
Serve shredded chicken on buns with your favorite toppings and sides.