Honestly I think they just mean "state". Yes, some states have more resources than others, but the ones without a lot of resources generally aren't engaging in cyber attacks, and "state" as a general category is good enough summary.

I think people say "nation state" in part just because it flows better rhythmically, and in part because of that whole "westphalian" thing; and because the word "state" has other confusing meanings (including in CS, state as in 'state machine'; and the 50 USA states).

But really on HN when talking about "threat actors", they mostly just mean "state-level". (See I had to add -level to make it rhythmically like 'nation state' again, the one syllable 'state' is just too short it just plops into your sentence ruining it)

[Hey, why is it called the United Nations instead of the United States anyway? Oops, cause there already is a United States. But the UN is clearly an organization of States not Nations. But the things are conflated and confused generally in European nationalist ideologies of the 18th-20th centuries, that have affected our vocabulary and concepts for these things, it's not just HN. "Nation" is often used as a synonym for "State", so "nation state" ends up just kind of doubling down]

I say "state-level actor".

Almost any contemporary liberal democracy (and not only those) at least formally defines itself as a state of it's citizens, not belonging to any particular "nation" (ie ethnicity basically) in particular. I don't see the point in distinguishing between states that are "nation" states or not in the 21st century, or think that it has a clear distinction.