So it’s complicated because there is a loose definition of nation as a synonym of country (eg nationalised industry, national anthem, ...) and a second more narrow definition which is the one used in the term ‘nation-state.’ But if the former definition of nation is being used then it is entirely redundant and writing a long confusing term instead of a well understood one is just lazy writing.

Wikipedia gives a more narrow definition of nation-state than you (but English dictionaries by their nature tend to give broad definitions) https://en.m.wikipedia.org/wiki/Nation_state