Place the chicken breasts in the bottom of your slow cooker.
Sprinkle with garlic powder, onion powder, salt, and pepper.
Pour 1/2 cup of BBQ sauce over the chicken, spreading it around to coat.
Cover and cook on low for 2 hours, or until the chicken shreds easily with a fork.
Shred the chicken using two forks right in the slow cooker or on a plate, then return it to the sauce and mix well.
Add more BBQ sauce to taste and let it sit on warm for 10–15 minutes before serving.