Prepare the Rub: In a small bowl, combine the smoked paprika, 1 tsp garlic powder, onion powder, salt, and black pepper. Mix well.

Season the Chicken: Pat the chicken breasts dry with a paper towel. This helps the rub adhere properly. Sprinkle the spice rub all over the chicken, pressing it gently into the meat to coat all sides.

Arrange in the Crockpot: Place the seasoned chicken breasts in the bottom of your slow cooker pot in a single layer.

Mix the Sauce: In a medium bowl, whisk together all the BBQ sauce ingredients: tomato ketchup, dark brown sugar, apple cider vinegar, Worcestershire sauce, Dijon mustard, liquid smoke, and the remaining ½ tsp garlic powder. Whisk until the sugar is dissolved and the sauce is smooth.

Combine and Cook: Pour the prepared BBQ sauce evenly over the chicken breasts in the slow cooker. Ensure they are well-covered. Place the lid on and cook on LOW for 4-6 hours or on HIGH for 2-3 hours. The chicken should be cooked through and very tender.

Shred the Chicken: Carefully remove the cooked chicken breasts from the slow cooker and place them in a large bowl. Using two forks, shred the chicken. It should pull apart very easily. What works best for me is to shred it while it's still warm.

Thicken the Sauce (My Secret Step!): This is key for a fantastic result. Pour the sauce left in the crockpot into a small saucepan. Bring it to a simmer over medium heat and let it bubble gently for 5-7 minutes, or until it has thickened to your liking. It should coat the back of a spoon.

Combine and Serve: Return the shredded chicken to the empty crockpot (or place it directly into the saucepan with the thickened sauce). Pour the thickened sauce over the top and stir everything together until the chicken is thoroughly coated. Let it sit for a few minutes to absorb all that flavour, then serve warm.