In a medium bowl, whisk together the chocolate pudding mix with two cups of cold milk until it starts to thicken. Refrigerate for 5 minutes to allow it to fully set.
Meanwhile, in a large bowl, use a hand mixer to combine the cake mix, eggs, vegetable oil, 1 cup of milk, and instant coffee. Beat for two minutes on medium speed.
Pour the cake batter into a well-greased 4-quart slow cooker.
Drop large spoonfuls of the pudding over the cake mix in the slow cooker. Do not stir. Spread the chocolate chips over the top.
Cover and cook on LOW setting for 4-5 hours or until set*.
Serve topped with ice cream or whipped cream.
Notes
*If a toothpick inserted into the cake comes away with no crumbs, it is doneLeftovers can be stored in the fridge in an airtight container for up to 3 days.