No, it uses native Nix directly on your machine - Linux, Mac, or Windows. Its integration with Docker is that it can _build_ Docker images from the Nix packages in your "devbox".
I'm assuming for windows it only works in WSL2? cause last time I checked nix wasn't compatible with native windows development, sadly
https://github.com/containers/toolbox/
https://github.com/89luca89/distrobox
With the downside of not having the option to select a Linux distro and being locked to the nixpkgs repositories?