This is the reply I was just about to leave as well! In Settings.

But I still like the Twitter embed, especially for videos, so that I am not leaving SN just to see the contents of the Tweet. It's only on the threads (and thus launching to a new tab) where I prefer to use Nitter.

So maybe even if I have the Setting for auto convert to Nitter left off (disabled), I can still get the Nitter for it. So for Posts that are Tweets, it remains the Tweet showing the Embed but there's also a launcher link/icon for the Nitter for that Tweet, so I can see the Tweet and thread in Nitter.

In the comments, same thing ... next to the Twitter link, automatically show a link/icon for the Nitter for that Tweet.