For the biscuits: Preheat the oven to 450°F (232°C). In a large bowl, combine the flour, baking powder, baking soda, and salt. Use a pastry cutter or the back of a fork to cut in the cream cheese and cold butter until the mixture has pea-sized clumps.
Stir in the mini chocolate chips. Add the cold buttermilk and gently mix until a shaggy dough forms.
Turn the dough out onto a floured surface and gently pat it into a 1 thick rectangle. Fold the dough in thirds (like a letter), then pat it back out to 1 thickness.
Use a 2 biscuit cutter to cut out rounds of dough. Re-roll the scraps and cut out additional rounds as needed. Place the biscuits 2 apart on a baking sheet.
Brush the tops of the biscuits with the melted butter. Place the baking sheet in the oven, then immediately reduce the temperature to 400°F (204°C). Bake for 18-20 minutes, until the tops are puffed and golden. Rotate the pan during baking if needed for even browning.
For the topping: While the biscuits are cooling, beat the cream cheese and powdered sugar together until smooth. Add 1–2 tablespoons of milk to achieve a spreadable consistency.
Spread the cream cheese glaze on top of each warm biscuit and serve immediately for the best flavor and texture.