We don't have synonyms for nation state yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are nation-state, nation states and native state.
(n) :
Alternative spelling of nation-state. [(politics) A political entity (a state) associated with a common national identity (historically, culturally, or ethnically; as with a nation) and a sovereign territorial unit.]
(n) :
Alternative spelling of nation-state. [(politics) A political entity (a state) associated with a common national identity (historically, culturally, or ethnically; as with a nation) and a sovereign territorial unit.]