Blue Ribbon Barbecue Chicken Cheeseburgers

In a large cast-iron skillet, cook the bacon over moderate heat, turning once, until browned and crisp, 8 to 10 minutes. Transfer the bacon to paper towels to drain and cut the strips in half. Pour off all but 2 tablespoons of fat from the skillet. Form the chicken into four 1/2-inch-thick patties and season generously with salt and pepper. Add the patties to the skillet and cook over moderately high heat until browned on the bottom, about 4 minutes. Flip the burgers, top with the cheese and crisp bacon and cook until the cheese is melted and the burgers are just cooked through, about 8 minutes. Spread barbecue sauce on the bottom buns and top with the cheeseburgers, sliced onion, tomato and lettuce. Close the burgers and serve right away.