Lightly coat a medium skillet with cooking spray. Heat skillet over medium heat. Lightly sprinkle chicken with salt and black pepper. Add chicken to hot skillet; cook until chicken is brown, turning once. Reduce heat to medium-low. Cook, covered, for 10 to 12 minutes or until chicken is tender and no longer pink.
Meanwhile, in a large saucepan or Dutch oven combine broth, garlic, crushed red pepper, and the 1/8 teaspoon black pepper. Bring to boiling. Stir in greens; reduce heat. Simmer, covered, for 9 to 12 minutes or just until greens are tender, stirring once or twice.
To serve, divide the greens and their juices between 2 dinner plates. Cut chicken diagonally into slices; arrange chicken slices on top of greens. Drizzle the chicken with balsamic vinegar and if desired, garnish with sweet pepper.