From Ender Scrolls
Map.png Nations

You can create a nation with the command /k nation create <nationname>, this will cost 500$. Set a kingdom as your nation capital with /k nation capital <kingdomname>. Place your nation nexus with /k nation nexus, you have to place the nation nexus in a claimed area that is not your kingdoms nexus claim.

Action Cost Command
Create 500 $ /kingdom nation create <nationname>
Rename 100 $ /kingdom nation rename <nationname>