The best place to draw the line is Texas. More national identity than Texas and you're a nation-state, less and you're a state. The nationality of Texas is undefined in this scheme, which is just as they would have it.

P.S. people call extremely well-funded cybersecurity adversaries "nation-state adversaries" because those three words start with the letters NSA. It's a joke about US national security being the greatest threat to US private security.

When used in the politico-social sense that invokes national identity, nation-state still takes as a minimum requirement the functional sense of Westphalian sovereignty, which Texas lacks. Texas would probably be considered a nation-state in both senses if it was a nation-state in the functional sense; but as a subordinate unit of a Westphalian sovereignty it is not a nation-state in the functional sense, much less the narrower social sense.