Preheat oven to 350°F (175°C). Line a 9x13 baking dish with parchment paper.
Make the base: In a bowl, mix chocolate cake mix, melted butter, and egg until dough forms. Press evenly into the bottom of the prepared pan.
Make the cheesecake layer: Beat cream cheese and pumpkin until smooth. Add eggs, vanilla, spices, and salt. Gradually beat in powdered sugar until creamy.
Pour cheesecake layer over the chocolate base and smooth the top.
Make the crumble topping: Combine flour, brown sugar, and cinnamon. Cut in butter until crumbly. Fold in pecans if using.
Top the cheesecake layer with crumble and sprinkle with chocolate chips.
Bake for 50–60 minutes until the center is set and the top is golden.
Cool completely, then refrigerate for 1 hour before slicing.
Serve with optional caramel drizzle or whipped cream.