I'm sure its not gone.

Some NMs had their spawns moved because of this, for instance, the Heftyhind goblin in Horutoto Ruins now spawns next to the door leading to his original spawn area.

Look around the zone for ~2 Mousse sitting alone, And kill them, He'll likely spawn from those.

With all these new mobs, I'm kinda sad they didn't add any new NMs, but eh, I Can't ask too much.