In a bowl, combine the sausage, prosciutto, chestnuts, olives and sage. Season with salt and pepper. Heat a small skillet and add a teaspoon of the stuffing. Saute until cooked through, about 2 minutes. Taste for seasoning and adjust seasoning in the stuffing mix, if necessary.
Place the turkey breast on the cutting board with skin side down. Flatten with your hands, season with salt and pepper and drizzle with olive oil to moisten. Spread stuffing on top and roll the turkey around the stuffing. Wrap kitchen twine around breast and tie tightly.
Place turkey in a roasting pan, drizzle with olive oil and season with salt and pepper. Roast until internal temperature of the turkey breast is 165 degrees F, about 1 hour or 12 to 15 minutes per pound.
Let rest 10 minutes, then snip off kitchen twine. Slice the turkey and arrange decoratively on serving platter. Pour pan juices over the slices and serve.