Preheat oven to 350°. Cut bacon strips in half. Place sheet of foil on a large baking sheet with sides. Spray with nonstick cooking spray. Place bacon on foil and bake until almost crisp, approximately 15 minutes. Remove from oven and plate lined with paper towels. Let bacon cool slightly.
Increase oven temperature to 375°. Wrap bacon around chestnuts and secure with toothpicks; place in a greased, foil-lined 9 x 13 pan. Combine Blackberry Syrup and chili sauce; brush sauce over bacon and water chestnuts. Reserve some sauce to brush on later. Bake uncovered until bacon is completely cooked, about 45 to 50 minutes. Brush on any remaining sauce. Makes 30 chestnuts.