N.E.S.T. or (Nuclear Emergency Support Team) was a team of technicians, scientists and engineers tasked with responding to any type of nuclear threat.
When a nuclear bomb brought by Second Wave was found at Norton Airfield, a NEST team arrived to try to disarm it. One of their technicians discovered the device was a decoy until they found the real device. The other technician tried to disarm it but he was unsuccessful. The bomb was then detonated safely at the Mojave Desert.
When a threat concerning nuclear rods was discovered on New York City, CTU New York director Brian Hastings ordered to have appropriate intelligence forwarded to the NEST team stationed at Fort Hamilton in Brooklyn. He also told Agent Cole Ortiz that as soon as the nuclear rods were recovered they were to be transported to the base. When the threat materialized and a bomb was left by the terrorists in an alley in Manhattan, a N.E.S.T. technician arrived at the site and used a robot to secure it.