NIHM is a holographic AI that was found by Jocho and Cyphi when they first stumbled upon the abandoned  LAB that they now all live in.  

She seems to be some sort of remnant of an experiment from long ago. She herself is the energy source that powers the lab and allows it to function off the grid.

Nihm was the one who first was able to make the link between MEGACITY and our current timeline, allowing the members of the lab to communicate with the past. She made this program open source, allowing anyone in their timeline with access to it to communicate with us through the internet. This program is VIRTUERA