In the slow cooker, whisk together BBQ sauce, brown sugar, apple cider vinegar, olive oil, garlic powder, onion powder, smoked paprika, and red pepper flakes.
Nestle the chicken breasts into the sauce mixture, turning to coat them evenly.
Cover the slow cooker and set it to cook on low for 6-7 hours or on high for 3-4 hours. The chicken is ready when it shreds easily with a fork.
Once cooked, shred the chicken using two forks and stir it into the sauce to soak up all the flavors. Serve warm.