A wiki page exists: https://nixos.wiki/wiki/Steam.
I started with simply nix-shell -p steam, which failed with a 404 while
trying to download some .deb. I updated my nixos channel, then tried again,
and got a shell.
Then I run the following and got a problem:
$ steam
The little Updating Steam popup appeared... Then another glXChooseVisual failed popup, with an ok button. Adding 32bit support in my NixOS
configutation fixed that error:
hardware.pulseaudio.support32Bit = true;
hardware.opengl.driSupport32Bit = true;
Run steam again and I was prompted for my credentials. A few windows
appeared (news, ads, ...).
When installing FTL, it offers to download it at ~/.local/share/Steam. It
starts in fullscreen without problem. Using alsamixer in another terminal to
change the sound volume works.
HRM starts, I hear the music, but the window is not visible... I have edited
the file ~/.local/share/Tomorrow\ Corporation/Human\ Resource\ Machine/settings.txt and set fullscreen = 0, and the game screen is now
visible.
Note that the game setting are not in ~/.local/share/Steam.