Prep the slow cooker: Lightly spray the crock with nonstick spray or use a liner for easy cleanup.
Whisk the sauce: In a bowl, combine BBQ sauce, chicken broth, brown sugar, apple cider vinegar, Worcestershire, mustard, onion, garlic, smoked paprika, chili powder, salt, and pepper.
Add the chicken: Place chicken in the slow cooker and pour the sauce over the top, turning pieces to coat evenly.
Cook low and slow: Cover and cook on Low for 4–6 hours or on High for 2–3 hours, until the chicken is fork-tender.
Shred: Remove chicken to a board and shred with two forks. Skim excess fat from the sauce if needed.
Return to sauce: Stir the shredded chicken back into the slow cooker to soak up all the juices. Taste and adjust seasoning.
Reduce if needed: For thicker sauce, uncover and cook on High for 15–20 minutes, or stir in a bit more BBQ sauce to coat.
Serve: Pile onto buns, top with coleslaw and pickles, and serve with chips or cornbread on the side.