COOK bacon in skillet on medium heat 5 min. or until crisp, turning occasionally. Remove bacon from skillet; drain on paper towels. Pour off all but 1 Tbsp. drippings from skillet.
ADD chicken to skillet; cook 5 to 6 min. on each side or until done (165ºF.) Top with Singles; cover. Remove from heat. Let stand 1 min. or until Singles are melted.
SPREAD baguette pieces with mayo; fill with chicken, bacon, lettuce and tomatoes. Serve with barbecue sauce.