PREHEAT oven to 350ºF. Beat eggs, cake mix, dry pudding mix, sour cream, oil, and water in large bowl with electric mixer on medium speed until well blended. Remove 1 cup of the batter; place in medium bowl. Add syrup and 1/2 cup of the chocolate chips to batter in medium bowl; mix well.
GREASE 12-cup fluted tube pan ; sprinkle with 2 Tbsp. of the pistachios and the remaining chocolate chips. Pour half of the plain pistachio batter into pan. Top with chocolate chip-pistachio batter, spreading to within 1/2-inch of edge of pan. (Do not let chocolate chip-pistachio batter touch the edge of pan). Top with remaining plain pistachio batter. Sprinkle with remaining 2 Tbsp. pistachios.
BAKE 1 hour or until wooden toothpick inserted near centre comes out clean. Cool 10 min.; remove to wire rack. Cool completely. Sprinkle with icing sugar before serving.