Despite not qualifying for the World Cup either, the Netherlands will take their place in the 12-team 'A' league at the expense of Chris Coleman's side.
The Nations League sees the 55 European national teams divided into four groups dependant on their rankings, with the top 12 going into League A.
The Republic of Ireland, who beat Wales to get into the World Cup play-off, are also in League B with Northern Ireland.
League A will consist of the 12 top-ranked teams. The next 12 teams will be in League B, the next 15 in League C and the remaining 16 in League D.
The group winners in Leagues B, C and D will gain promotion and those who finish bottom of the groups in Leagues A, B and C will be relegated.