1 (2 ounce) bag chopped pecans or walnuts
1 (6 ounce) bag semisweet chocolate chips
1 (18.15 ounce) box white cake mix
1 (3.4 ounce) box pistachio instant pudding mix
1/2 cup granulated sugar
1/2 cup water
1/2 cup orange juice
1/2 cup vegetable oil
1/2 cup chocolate syrup
Preheat oven to 350 degrees F. Oil and flour a 12-cup Bundt pan. Sprinkle the pecans and chocolate chips evenly around the bottom of the pan, set aside.
In a large bowl, use mixer to combine the cake mix, pudding mix, sugar, water, orange juice, oil and eggs. Blend 1 minute at low speed, scraping the bowl occasionally. Beat 2 minutes or more at medium speed, until the mixture the smooth.
Remove 1 cup of batter to a small bowl and add the chocolate syrup to it, stirring until the mixture is uniform; set aside.
Pour the remaining batter into the prepared pan, then pour the chocolate batter over it in a ring around the pan, avoiding the edges of the pan. Swirl the chocolate batter into the white batter with a dinner knife.
Bake 55 to 60 minutes, until the cake springs back when touched lightly with a finger and a wooden pick inserted in the center comes out clean. Set on a wire rack to cool about 20 minutes. If the cake has not shrunk slightly from the side of the pan, loosen it lightly with a knife. Cover with a serving plate, invert, shake and remove from pan. Cool completely before serving.