We use it for devshells, and it’s awesome. New devs install nix and direnv and they instantly have all the right versions of all of our tooling. A first day setup process is now done in minutes instead of a day. Flakes made it possible for us to package up internal and external tools and ensure consistency across a team.

I have no experience running it in production, but I imagine if you don’t want to use containers it’d be a pretty good option.