I think you are conflating senses of the word, or rather you are defaulting to a very specific usage. There's the usage "Iranian national cuisine" which as you

I think you are conflating senses of the word, or rather you are defaulting to a very specific usage. There's the usage "Iranian national cuisine" which as you say is inherently political in nature because we mean "nation" in a civic and territorial sense, subsuming e.g. Persian, Azeri, Kurd cuisines, among others. There may be objections to specific inclusions or exclusions as we are considering Iran as a civic and political entity with borders, as you say But it's perfectly fine to refer to "Kurdish national cuisine" or Persian national cuisine or Azeri national cuisine even in the absence of any nation state. So I'm using the term in an ethnocultural sense, not in the sense of something sanctioned by a nation state or a political entity. See also black nationalism or Kurdish nationalism -- no state is required here. You have political mobilisation around an ethnocultural designation rather than a government