Arrival by car: Coming from Hermagor or Kötschach-Mauthen, you drive via the B111 (Gailtal Road) towards Tröpolach/Nassfeld junction - from there you continue on the B90 (Nassfeldpass Road) to the former border crossing.
Public transport arrival:
The most sustainable travel option is by train (coming from Villach) to Hermagor. From Hermagor, you can proceed by shuttle train, as well as bus / ski bus, to the town of Tröpolach.
Alternatively, there is also the possibility to arrive by bus from Kötschach-Mauthen or Villach to Hermagor or Tröpolach.
From Tröpolach, you then take the Millennium Express up the mountain before descending on the Madritschenbahn, reaching the starting point of your snowshoe hike at the Nassfeldpass border after a few minutes on foot.
Details at - Nassfeld Mobility Information and Kärntner Linien Route Planner