Cloudflare really doesn't make much of a difference for HN. The last front page traffic I saw (~a week ago?) was still at most a handful of QPS. Any nginx instance with default configuration serving static files from any modern computer should be able to handle that (given that your link is big enough).

Now if you reach the top of a large subreddit, or have a viral tweet with a link to you, that's a different order of magnitude. HN is just not that large.