Place the chicken breasts in the slow cooker.
In a mixing bowl, combine the BBQ sauce, brown sugar, apple cider vinegar, Worcestershire sauce, smoked paprika, garlic powder, onion powder, salt, and black pepper. Stir well to combine.
Pour the BBQ sauce mixture over the chicken in the slow cooker, making sure the chicken is evenly coated.
Cover the slow cooker and cook on low heat for 6-8 hours or on high heat for 3-4 hours. The chicken should be cooked through and tender enough to shred.
Once the chicken is cooked, remove it from the slow cooker and transfer it to a cutting board. Use two forks to shred the chicken into bite-sized pieces.
Return the shredded chicken to the slow cooker and stir it into the sauce to coat evenly. Allow it to cook for an additional 15-20 minutes on low heat to absorb more flavor.
Serve the pulled BBQ chicken on hamburger buns or sandwich rolls. You can top it with additional BBQ sauce or your favorite coleslaw, if desired. Enjoy!