Flatten chicken to 1/4-in. thickness; sprinkle with salt and pepper. Prepare stuffing mix according to package directions. Meanwhile, in a small skillet, saute pecans in butter until lightly browned; add to the stuffing.
Place 1/2 cup stuffing down the center of each chicken breast half; roll up and secure with a toothpick. Place seam side down in a greased shallow 1-qt. baking dish.
Spoon soup over chicken; sprinkle with remaining stuffing. Cover and bake at 400° for 25-30 minutes or until chicken is no longer pink. Remove toothpicks. Yield: 4 servings.