The race to earn promotion to the league above or even qualify for the finals – all while avoiding the drop to the tier below – is beginning to hot up ahead of next month's last batch of group games.
With potential places at Euro 2020 up for grabs, not to mention seedings for the qualifying phase, it's within some teams' interests to take their next couple of matches pretty seriously.
Here, we look at the state of play ahead of the last games of matchday five and the matchday six fixtures in November.
League A: race to the finals
Group 1: France, Netherlands, Germany
Standings: France are top with four points from two games, one above Netherlands and three clear of Germany. If Germany lose to France on Tuesday, they cannot finish higher than second.
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Remaining matches: France v Germany (16/10), Netherlands v France (16/11), Germany v Netherlands (19/11)
Group 2: Belgium, Switzerland, Iceland
Standings: Belgium and Switzerland have six points; Roberto Martinez's side, who have a game in hand, are top thanks to their head-to-head record. Switzerland must beat them by two goals next month to qualify for the finals. Iceland, with no points, have been relegated.
Remaining matches: Belgium v Iceland (15/11), Switzerland v Belgium (18/11)
Group 3: Portugal, Italy, Poland
Standings: Portugal are top with six points from two games, two ahead of Italy. They will reach the finals with a draw against Italy in their last match; the Azzurri must win and hope Portugal then fail to beat Poland to have any chance. Poland have been relegated.
Remaining matches: Italy v Portugal (17/11), Portugal v Poland (20/11)
Group 4: Spain, England, Croatia
Standings: Spain are two points above England at the top. They will reach the finals if they beat Croatia. If they don't, England can qualify with a win over Croatia, who need two victories to finish top themselves.
Remaining matches: Croatia v Spain (15/11), England v Croatia (18/11)
Race for promotion
League B: Ukraine need a draw to go up, as do Russia, although they will be promoted regardless if Sweden don't beat Turkey next month. Bosnia-Herzegovina are also one point away from top spot. Austria, Czech Republic, Denmark, Republic of Ireland, Slovakia, Sweden and Wales can also still be promoted.
League C: Israel and Finland are a point away from promotion. Bulgaria will go up if they beat Norway on Tuesday and Cyprus don't beat Slovenia. Serbia will top their group next month if they beat Montenegro and Romania lose to Lithuania. Scotland, Albania, Greece, Norway, Cyprus and Montenegro can also still be promoted.
League D:Georgia will go up with a win on Tuesday or if both Group 1 games finish in draws. Luxembourg will be promoted if they beat Belarus, as will Kosovo if they defeat Malta and Azerbaijan fail to beat Faroe Islands. Macedonia will be up with a win over Armenia, and if Liechtenstein and Gibraltar draw. Andorra, Kazakhstan, Latvia, Belarus, Moldova, Azerbaijan, Faroe Islands, Liechtenstein, Armenia and Gibraltar can also still be promoted.
Battle against relegation
League A: Iceland and Poland are relegated. Germany will be down if they don't win another game, as will Croatia. France, Netherlands and England can also go down.
League B: Sweden will be down if they lose to Turkey or fail to win next month. Northern Ireland will be relegated if Austria take at least a point against Bosnia-Herzegovina. Ukraine, Czech Republic, Slovakia, Turkey, Austria, Denmark, Wales and Republic of Ireland can also go down.
League C:Estonia will be relegated with defeat to Hungary. Slovenia will be down if they lose to Cyprus and Norway avoid defeat to Bulgaria. Lithuania need six points and to hope Montenegro beat Romania. Israel, Scotland, Albania, Greece, Hungary, Norway, Cyprus and Romania can also go down.
Why does it matter?
The four group winners in League A will go into the Nations League Finals draw on December 3. They are also guaranteed at least a play-off place for Euro 2020, if they fail to get through qualifying.
The promoted teams from Leagues B, C and D will move up a League for the next Nations League tournament. They are also guaranteed at least a play-off place for Euro 2020, if they fail to get through qualifying.
The relegated teams from Leagues A, B and C will move down a League for the next Nations League tournament.
Every team's final position will determine their seeding for Euro 2020 qualifying, the draw for which takes place on December 2.
