Preheat your oven to 375°F and line a large baking dish with foil for easy cleanup. Pat chicken pieces dry with paper towels to ensure the spice rub adheres properly.
Combine smoked paprika, brown sugar, garlic powder, onion powder, black pepper, and salt in a small bowl. Rub this mixture generously over all chicken pieces, coating both sides thoroughly for maximum flavor impact.
Heat olive oil in a large skillet over medium-high heat and sear the chicken for 2 minutes per side. Don't skip this step—it creates a golden crust that seals in juices during baking.
Arrange sliced onions on the bottom of your baking dish and place seared chicken pieces on top. Pour chicken broth around the chicken, then whisk together BBQ sauce, apple cider vinegar, Worcestershire sauce, and liquid smoke, pouring this mixture over the smoky juicy BBQ chicken baked pieces.
Bake for 30-35 minutes at 375°F until chicken reaches 165°F internally. Dot the top with butter during the last 10 minutes to create an extra-glossy finish on your sticky chicken pieces.
Remove from oven and let rest for 5 minutes before serving to allow juices to redistribute throughout the meat.