Bake chocolate cake in a 9x13 inch pan according to package directions and let cool for 10 minutes.
Poke holes about an inch apart across the warm cake with a wooden spoon handle.
Whisk pudding mixes with milk for 2 minutes until slightly thickened, then pour immediately over the cake so it seeps into the holes.
Refrigerate for at least 1 hour until pudding is fully set.
Fold marshmallow fluff into whipped topping and spread evenly over the top of the cake.
Sprinkle with crushed graham crackers and mini chocolate chips before serving.