What is a Psychic Nullifier?
Just another misc item along with
Acess Card, COC Badge, gag ball (;-)), n' some more stuff.
It has no use currently
Not true, actually. Ball gag makes everything you say turn into grrmmmgrmgmr, goggles make all eyes shots headshots, and I heard psychic nullifier has something to do with speech, maybe hearing whispers or something.
As to the thing about fallout use, nullifier in f2 was completely useless and in f1 allowed you to pass Master's corridor without getting hurt. I doubt that the Master is in this game, so it has either a changed use or no use. Since it is actually possible to equip it into the head slot, when it was a misc. item in fallout, it hints at some use being available.