I've been using NixOS and Nix to install things in my servers. It's very mature. Most things I need are packaged, including not so popular utilities like isync

I've been using NixOS and Nix to install things in my servers. It's very mature. Most things I need are packaged, including not so popular utilities like isync or notmuch. However, I'm curious about containers. For example systemd-nspawn seems like a simple way to achieve many of the functionality NixOS brings into the table.