Cook bacon slices in a skillet until crispy. Remove to drain on paper towels. Pour off all but 1 tsp. bacon drippings.
Pound chicken breasts to an even thickness. Pan grill until golden brown on each side and cooked through, about 5 minutes per side or until chicken registers 165 degrees on an instant read thermometer. Remove from pan.
Butter bread slices and add to skillet. Top each slice with shredded cheese and grill until golden brown on the bottom and the cheese has melted. Place chicken breasts on two slices of bread.
Top each grilled chicken breasts with a schmear of bbq sauce, two slices of crispy bacon, sliced tomato, diced jalapeno & scallion and a second cheesy bread slice.