Combine the olive oil, vinegar, prunes, olives, capers, sun-dried tomatoes, bay leaves, garlic, oregano, 1 tablespoon salt, and 2 teaspoons pepper in a large plastic storage bag. Add the chicken to the marinade. (Squeeze out the air to make sure the chicken is fully covered with the marinade.) Refrigerate for 4 hours and up to overnight.
Preheat the oven to 350°F.
Place the chicken along with all the contents and marinade in one layer in a large roasting pan. Sprinkle with the brown sugar, 2 teaspoons salt, and 1 teaspoon pepper. Pour the wine around the chicken. Evenly distribute the walnuts over the top.
Roast for 45 to 55 minutes or until the internal temperature of the chicken is 165℉. Remove the pan from the oven, cover tightly with aluminum foil, and allow to rest for 10 minutes. Discard the bay leaves.