B747-400
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Ground Event / Encounter Loss Of Aircraft Control; Ground Event / Encounter Weather / Turbulence; Ground Excursion Taxiway
General None Reported / Taken
Aircraft; Weather
We were turning the corner on Taxiway 1 to takeoff on runway XXL; but braking action was nil and the nose gear exited the taxiway.
B747 Captain reported that while making a turn; the nose gear exited the taxiway and braking action was NIL.