Nations and States are different things. A nation designates an ethnic population tied together by history and custom. "A people who share common customs, origins, history, and frequently language; a nationality." States are political entities.
Nations often have ties of identity (e.g, Quebec, the "First Nations" - aboriginal people - in Canada, the Kurds in Turkey & Iraq, the Jews), even if there are no state mechanisms, or if the mechanisms are submerged under other state apparati.
Nation-state: The assumption of modern politics.
A political unit consisting of an autonomous state inhabited predominantly by a people sharing a common culture, history, and language.
There are relatively few of these around. Most states have multiple historical descriptions. Some have more than one language.