Prepare grill to medium-high heat. Sprinkle chicken evenly with 1/4 teaspoon salt and 1/4 teaspoon freshly ground black pepper. Place chicken on grill rack coated with cooking spray, and grill for 6 minutes on each side or until chicken is done. Keep warm. Combine tomatoes, 1 1/2 tablespoons dressing, and olives in a medium skillet over medium heat, and cook for 2 minutes or until tomatoes soften slightly and mixture is thoroughly heated, stirring occasionally. Brush chicken with remaining 1 1/2 tablespoons dressing. Cut each chicken breast half into 3/4-inch slices. Top each chicken breast half with 1/4 cup tomato mixture. Sprinkle each serving with 2 tablespoons cheese and torn basil leaves, if desired.