nation vs political unit

nation and political unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
nation	Yes	No	No	No
political unit	Yes	No	No	No

As nouns, political unit is a hypernym of nation; that is, political unit is a word with a broader meaning than nation:

Other hypernyms of nation include political entity.

nation (noun)	political unit (noun)
a politically organized body of people under a single government	a unit with political responsibilities
the people who live in a nation or country
a federation of tribes (especially Native American tribes)