Prepare the Machine: Place the Ninja SLUSHi upright on a flat counter for at least 2 hours. Assemble the condensation catch, auger, vessel, bail handle, and drip tray, then plug in the machine.
Add Coke Zero: Pour 32 ounces of cold Coca-Cola Zero Sugar through the easy-fill port. Close the cover.
Freeze the Slush: Turn on the Ninja SLUSHi and select SLUSH. Let it run for about 20–25 minutes, or until the machine beeps and the LEDs stay solid.
Dispense and Serve: Place a chilled glass under the dispensing handle. Slowly pull the handle to dispense the slush, then release it to stop. Serve immediately.