You're probably thinking of libreddit, which indeed shut down when Reddit's API access was shut off. Now most libreddit instances out there either return a 429 error or simply don't exist anymore.
Nitter on the other hand has been doing fine on my end. Instances with heavy traffic, such as nitter.net, do frequently run into rate limiting errors. But if you use relatively more obscure instances, then almost nothing has changed.
They keep working with a workaround, by using guest tokens handed out to the Android application. So, until they change the functioning of the app, it will keep working.
Although not out of the box right now, it requires running some external scripts to grab guest accounts and running a build off a branch or fork. See https://github.com/zedeus/nitter/issues/983
Nitter on the other hand has been doing fine on my end. Instances with heavy traffic, such as nitter.net, do frequently run into rate limiting errors. But if you use relatively more obscure instances, then almost nothing has changed.