Heat the olive oil in a medium skillet over medium heat. Add the carrots, celery, onion, and garlic. Season with salt and pepper to taste. Cook until the vegetables are just soft, about 5 minutes.
Spread 1/8 of the vegetable mixture onto the center of each half of chicken breast and roll up. Place in a casserole dish, seam side down. Cover with ½ of the RAGÚ® Old World Style® Traditional Sauce.
Cook 30 minutes or until the internal temperature of the chicken reaches 165 degrees.
Combine the remaining RAGÚ® Old World Style® Traditional Sauce and sour cream and pour into the casserole dish. Return the casserole to the oven for 3-4 minutes, until the sauce is just hated through, but not boiling.