Preheat oven to 350F. Beat cake mix, eggs, sour cream, oil and 1/2 cup water in large bowl with electric mixer on low speed just to moisten, scraping side of bowl often. Beat on medium speed 2 minutes. Stir in nuts.
Spoon into greased and floured 12-cup fluted tube pan or 10-inch tube pan.
Bake 50 minutes or until toothpick inserted near center comes out clean. Cool 10 minutes; loosen from side of pan with spatula or knife and gently remove cake. Cool completely on wire rack.