HEAT oven to 375ºF.
BROWN meat with vegetables in skillet on medium-high heat; drain. Stir in 1/4 cup barbecue sauce.
PLACE chicken in 13x9-inch baking dish. Squeeze lemon juice over outside of chicken and inside body cavity. Season with pepper. Stuff chicken with meat mixture. Brush with remaining barbecue sauce.
BAKE 45 min. Reduce oven temperature to 325ºF. Cover chicken with foil; bake 30 min. or until done (165ºF). Let stand, covered, 10 min. before serving chicken with the stuffing.