In large bowl, beat cake mix, 3/4 cup milk, the oil, eggs and sweet potatoes with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes. Stir in 1 cup chopped pecans. Pour batter into pan. Bake 20 to 25 minutes or until toothpick inserted in center comes out clean. Cool completely in pan on cooling rack, about 1 hour.