Short answer, BIG TANK.
Long answer, big tank plus big filtration plus chilling unit plus...
Not sure if this is for the hobby or public aquarium, but in either case, are you aware of the new regulations regarding the export of nautiluses? Recent conservation initiatives have resulted in the first regulation of nautilus trade so exporting nautiluses now requires certain things. The primary requirement is that any country wishing to export nautiluses (live, dead, shell, jewelry, etc.) must supply additional paperwork showing that the export does not impact wild populations. This all came into effect in January 2017.
In my opinion, tank mates for nautiluses should only include other invertebrates.
Greg