In a slow cooker, combine BBQ sauce, grated onion, olive oil, Worcestershire sauce, and brown sugar.
Stir well to create the sauce.
Add chicken breasts and turn to coat evenly.
Cover and cook on low for 6–7 hours or high for 2–3 hours.
Check that the chicken reaches an internal temperature of 165°F (74°C).
Remove the chicken and shred using two forks.
Return shredded chicken to the slow cooker and mix with the sauce.
This Slow Cooker BBQ Chicken is perfect served in sandwiches, wraps, or over rice.