Nation-state actors are just illegal criminal organizations, authorities, backed by governments. Above the law, with large budgets.
I mean, maybe you meant illegal, in the sense that they are not always in clear legal status (e.g, NSA doing illegal things), but I think for the reader "legal criminal organizations" makes more sense to the point.
Another way to write it maybe would be "sanctioned criminal organizations" but that would be confusing with the secondary meaning of sanctioned. Oh language :(