Nemesis mod for the Map Device

Hi;
So, I want to try my luck with ancient orbs and unique belt, to try crafting the Headhunter.
But it seems like I need the nemesis mod, which the map device does not provide.
Can't manage to find the information needed as to how generating this mod;
Information would be appreciated;
Thanks

map device mods change every 3 months. this mod is currently NOT available at all. youll have to hope it comes back next league.

oh, too bad...
thanks for the answer anyway