Nix is also cross platform. I have a ZSH and NVim configuration from my NixOS laptop, and when I got a company MacBook, it was extremely simple to use that same configuration and get an identical setup.
That's two dotfiles and two directories each for my setup, which i just rsync over if I feel like. Are you talking about installing necessary depencies or something? I can't think of a ton of examples but maybe a language server? Not that it's strictly part of nvim. Some details perhaps?