Preheat the oven to 350°F (175°C). Grease a 9×9-inch baking pan.
Mix the graham cracker crumbs, melted butter, and sugar in a bowl. Press this mixture into the bottom of the pan to form the crust.
Bake for 8-10 minutes, then remove from the oven and let cool.
Prepare the cheesecake filling:
Beat the cream cheese and sugar together in a large mixing bowl until smooth. Add the sour cream and vanilla extract, then continue beating until fully combined.
Add the chocolate chips:
Stir in the mini chocolate chips.
Assemble and bake:
Pour the cheesecake mixture over the cooled crust and spread it evenly.
Bake for 30-35 minutes, or until the center is set and the top is slightly golden.
Cool and serve:
Let the bars cool to room temperature, then refrigerate for at least 2 hours to allow them to set.