stir together the barbecue sauce, apple cider vinegar, maple syrup and chili powder in the base of a slow cooker. then add the chicken breasts, turning to coat in the sauce.
put the lid on the slow cooker, then cook on low for 3-4 hours.
use an electric hand mixer or two forks to shred the chicken. then return to the slow cooker, tossing it back up in the sauce.
BBQ pulled chicken is typically served on a bun with slaw.