Your organisation falls under NIS2 if it operates in one of the 18 sectors listed in Annex I or Annex II of the directive and meets the medium or large enterprise size threshold (50+ employees or €10 million+ annual turnover). Certain entities, including DNS providers, top-level domain registries, and public administration bodies, are in scope regardless of size, and smaller suppliers can be pulled in indirectly through contracts with in-scope customers. If that's all you needed, you now know enough to start classifying your entity. Everyone else should read on, because the size rule, the sector list, and the exceptions each have details that change the answer.