Nexus Core Agents are not particularly different from the AAHW's 1337 Crew Agents, although they are deadlier as they can go in tactical packs to overwhelm opponents. It is shown in some stages such as Deep Storage and Shakedown that they are often mistreated and labelled as nerds by security agents and they rely on them for protection, alongside releasing experiments.
They wear lab coats and visors with light blue highlights. In MADNESS: Project Nexus, they are introduced in Story Mode's stage Deep Storage and are all armed with laser-based weaponry, typically the Laser Pistolette with the occasional Laser Rifle, although they are still as weak as an AAHW grunt and unlike their Project Nexus Classic counterparts they will engage enemies in combat.
In Madness: Project Nexus (Classic), the Nexus Core Scientists appear to be unarmed civilians and are neutral to Christoff, although some of them had maybe been caught in the crossfire between him and Phobos' agents.