Once the excess filament has been removed, loosen the nozzle by a quarter turn using the wrench provided, then either power off or cool down the printer.
Do not attempt to fully remove the nozzle while the printer is at operating temperature. Allow the nozzle to fully cool before removal.
Before removing the nozzle check the temperature by bringing the back of your hand near the nozzle; do not touch it. If you feel any heat on the back of your hand, then wait another 10-15 minutes before removing the nozzle.