Place the chicken breasts in the bottom of the crockpot.
In a medium bowl, whisk together BBQ sauce, Italian dressing, brown sugar, and Worcestershire sauce.
Pour the mixture over the chicken, making sure each piece is well coated.
Cover and cook on low for 6-7 hours or on high for 3-4 hours, until the chicken is cooked through and tender.
Shred the chicken with two forks directly in the crockpot, then stir to coat it in the sauce.
Serve warm on buns, over rice, or alongside your favorite sides.