Yes. However many domains can host the renderer. Currently there are three domains and any of them can render the same sites.

It is also possible to run it just on localhost and access all the same sites.

I was looking into nsites earlier today and it does seem like a good match.

If it was something useful you could also bundle the site viewer in an app (I have a demo of this on GitHub with nowhere added inside bitchat as they seemed like a perfect match for each other)