Combine first 6 ingredients in a small bowl; set aside.
Place chicken between 2 sheets of heavy-duty plastic wrap; flatten to 1/4-inch thickness, using a meat mallet or rolling pin. Cut each breast into 2-inch pieces.
Combine flour, salt, and pepper in a small bowl. Dredge chicken pieces in flour mixture. Heat oil in a large nonstick skillet over medium heat. Add chicken; cook 4 minutes on each side or until done. Remove chicken from skillet; keep warm.
Stir broth mixture, and add to skillet. Cook over medium heat until mixture is thickened and bubbly, stirring constantly. Stir in margarine. Spoon sauce over chicken; sprinkle with parsley, if desired.