An hour or two before cooking pound out the chicken breasts between two pieces of plastic wrap using a meat mallet or a skillet to an even thickness. Season with salt and pepper and place in a large bowl - cover with barbecue sauce and marinate in the refrigerator.
Preheat the oven to 400 degrees F. Bake the chicken until cooked through to an internal temperature of 165 - 175 degrees F.
Remove the chicken from the oven, turn on the broiler and sprinkle the cheese over the chicken. Place under the broiler until the cheese is melted about 2 minutes - checking on it every 30 seconds.
To serve garnish the chicken with the tomatoes and bacon (you can crumble it or leave it in big pieces).