Preheat the oven to 375 degrees and grease a 9-inch springform pan with nonstick cooking spray or coconut oil.
Prepare the brownie mix according to the package directions and pour into the pan. Bake in the preheated oven for 20 minutes, until brownie is set but not fully cooked.
While the brownie crust is baking, combine the cream cheese, cane sugar, flour, and vanilla in a large bowl or stand mixer bowl and mix on low until smooth and combined.
Add the milk and beaten eggs on low until well combined.
Pour the cream cheese mixture into the pan over of the brownie crust.
In a small microwave safe bowl, add the chocolate chips and coconut oil. Melt in 30-second increments in the microwave, stirring between each addition.
Once fully melted, drop the chocolate into the cheesecake mixture in a dot pattern and drag a small spatula or knife through the chocolate dots to create a marbled swirl effect.
Bake the cheesecake for an additional 30 to 40 minutes. Check at starting at the 30-minute mark to see if the outside edges are set when the pan is gently shaken. (Tip: To avoid cracking, place a pan of water on the bottom rack of the oven while the cheesecake is baking.)
After baking, cool the cheesecake for 15 minutes on a wire rack. After 15 minutes, loosen the edges of the cake from the pan with a thin knife and remove it from the springform pan before continuing to cool the cake until it reaches room temperature, approximately 30 minutes.
Chill the cheesecake for a minimum of 4 hours, but the dessert is best served if refrigerated overnight.