there is at least one community-managed flake to connect a NixOS machine to an OpenZiti overlay network, but i don't think there is an official NixOS module yet:

github.com/rochecompaan/openziti-nix

if your focus is trying it rather than distributing consistent versions to many folks, you can also use the ziti-edge-tunnel binary, define a systemd service and add identities (a given app or device can belong to (n) OpenZiti overlays via (n) different identities).