1Spray 6-quart slow cooker with cooking spray. In large bowl, beat Cake ingredients with electric mixer as directed on cake mix box. Pour into slow cooker.
2In medium bowl, beat pudding mix and 2 cups milk with whisk as directed on box. Pour into slow cooker over cake batter. Do not mix. Sprinkle chocolate chips over top.
3Cover; cook on Low heat setting 2 hours 30 minutes to 3 hours or until cake is set and pudding is beginning to bubble out of cake.