Lightly spray the inside of a large crockpot or slow cooker with non-stick cooking spray. You can also use a slow cooker liner for easier cleanup.
Pat the chicken breasts dry and season both sides with salt, black pepper, garlic powder, and onion powder.
Place the seasoned chicken breasts in the bottom of the slow cooker.
In a medium bowl, whisk together the barbecue sauce, Italian dressing, Worcestershire sauce, and light brown sugar until smooth.
Pour the sauce mixture evenly over the chicken, making sure the chicken is well coated.
Cover with the lid and cook on HIGH for 2 1/2 to 3 hours or LOW for 5 to 6 hours, until the chicken reaches an internal temperature of 165°F (74°C).
Once cooked, shred the chicken directly in the crockpot using two forks.
Stir the shredded chicken into the BBQ sauce and allow it to sit for a few minutes so it absorbs the flavorful sauce.
Serve the crockpot BBQ chicken on buns, over rice, in tacos, on salads, over nachos, or as a simple main dish.
The cooking times and 165°F/74°C target follow the recipe information provided in the source versions of this recipe.