We have quite a few machines running ITS, LISPM, and other OSs on the chaosnet today. See https://chaosnet.net for details.
Chaosnet today: https://chaosnet.net/
Related:
A Short History of Chaosnet - https://news.ycombinator.com/item?id=29927718 - Jan 2022 (1 comment)
A Short History of Chaosnet (2018) - https://news.ycombinator.com/item?id=19480577 - March 2019 (6 comments)
It says "Usage of Chaosnet presumably waned as Lisp machines became less and less popular." That's basically true, but there was substantial Chaosnet usage from multi-user machines (e.g., UNIX, VMS, TOPS-20). Once you had a Sun-3 or MicroVAX, though, you probably left Chaosnet behind.
Arguably lisp machines were the last bastion of chaosnet, as even in somewhat later models chaosnet over ethernet could be easier to setup than other protocols.
That said, Symbolics Genera made all of It's services work over I think all protocols it supported (so chaosnet, serial lines, IP, etc)