A simple userscript should do the trick instead of HN changing the URL.

    var nitterUrl = window.location.toString().replace('twitter.com', 'nitter.net');
    window.location.replace(nitterUrl);

Though if you want to be sure you never send a single packet to Twitter, you'll have to make a script that operates on all sites and rewrites URLs in the anchor tags.

Edit: Just saw someone mention this extension which could be a better option https://github.com/SimonBrazell/privacy-redirect

That just sets you up for long term issues similar to the ones associated with URL redirectors and shorteners.