Heat broiler. Brush chicken with 1/2 cup barbecue sauce.
Broil for 4 to 5 minutes on each side.
Slice breasts into long 1/2-inch-thick slices. Mix with remaining sauce, corn and salt. Keep warm.
Gently warm tortillas according to package directions.
To serve, place lettuce on tortillas. Top with chicken. Garnish with cheese and scallions. Roll up.