In a large bowl combine flour, baking powder, baking soda, and salt together.
Add chilled butter pieces and cold mashed potatoes to flour mixture. Using a pastry blender or forks, break up butter and mashed potatoes evenly in flour mixture.
Add cheddar cheese, milk and chives to biscuit mixture and stir until everything is evenly mixed.
Heat oven to 425 °F. Using your hands, drop about 8-9 biscuits in a greased cast iron pan or regular baking pan and bake for 20 minutes.
Tip: if you preheat your baking pan while you preheat your oven. The hot pan will give a nice crispy bottom crust to your biscuits.