Because OSGeo-Live is now including nik4 in its osm installer, there is more need for a nik4 package.
Upstream does not tag releases yet, but is considering it now that OSGeo-Live includes it, so that latest git snapshot has been packaged. Packaging is available in the Debian GIS git repository: https://anonscm.debian.org/cgit/pkg-grass/nik4.git The package has also been uploaded but will need to pass the NEW queue. Kind Regards, Bas