A nation is a loosely defined concept popularised at the end of the nineteenth century by the French and German with each a different definitions relating to a mostly fantasied shared history and vague appeal to a common identity and whose usefulness diminishes quickly when it’s not about justifying war and persecution.

Meanwhile what you are talking about is a country: a sovereign legal entity which actually exists.

Sounds more like a country than a nation. Nations are more cultural which is why there can be a Navajo nation or a Kurd nation without there being a Kurdistan and the Navajos being part of the United States with limited autonomy. As is the case with anything in this sphere, the edges can be a bit fuzzy and not everyone agrees on the definition of nation.

A nation is about a shared identity that binds people together, not necessarily ruled by a single government. For example, the Kurdish nation is spread across several states, so not ruled by a single government but a nation nonetheless. Whereas states can encompass various nations. In short, the Russian nation is different from the Russian state, and calling the Russian state a nation-state can be misleading.

American Heritage says a nation is a large group of people with one government. Merriam Webster says a nation is an area of land with one government. Leaving people out entirely. Cambridge dictionary has the combination of those as the first definition, but adds the cultural definition second. It seems like this word is flexible enough in common usage to cover both uses with context necessary to distinguish usage. Dieing on that hill seems excessive.

It depends, I think the distinction is more important if you're a member of an endangered, stateless nation, because in that case the term nation-state implies that your people does not exist as a nation, whereas if you belong to the dominant nation within a state, then it's the other way round, it's in your interest to reinforce the idea that there's one nation (as opposed to multiple ones), and therefore prefer the term nation-state.