Just from quick look it seems to only contain 5 static binaries.
So you could download/unpack it just to check if it runs at all on macos:
curl -O https://cdn.teleport.dev/teleport-16.1.0.pkg
xar -xf ./teleport-16.1.0.pkg
zcat ./Payload | cpio -i
If it does work, you can do the same in .nix package (fetchurl, unpackPhase, copy binaries into place in installPhase).
There seems to be a few examples in nixpkgs: