Preheat oven to 350 degrees.
Combine cake mix, pudding mix, and sugar with a wire whisk to remove large lumps.
Add oil, eggs, and sour cream, stirring until smooth.
Stir in chocolate chips.
Pour batter into a greased and floured 12 cup bundt pan.
Bake for 1 hour or until a toothpick inserted in center comes out clean.
Cool in pan for 10 minutes and then remove to wire rack to cool completely.
Sprinkle with sifted powdered sugar.