Nat is a supervisor for the National Security Agency.
When Steve is left behind while CIA agents go to lunch in "N.S.A. (No Snoops Allowed)", he gets a mysterious message to exit and head to the nearby N.S.A. Headquarters where he meets Nat, who knows a lot about him through their spying. He shows Steve that the N.S.A. is loaded with nerds like him, who try to obtain secrets to undermine their CIA counterparts. Their wildest dream is to get secrets from Stan's computer, but find out from Steve that he still uses outdated floppy disks to store information which they can't reach.
When Steve is shown Stan and Avery Bullock laughing at him behind his back, he agrees to obtain the disks for the N.S.A. but as soon as he turns them over, finds he is turned loose as no longer needed as well. He tries to tell Stan what he has done, but is banished to a tree fort in a thunderstorm where Stan arrives later, claiming it was part of a plan to avoid being overheard. Together, they raid N.S.A. headquarters, and, after giving Nat various abuse including an atomic wedgie, destroy the computers containing the secrets.
Nat is voiced by Seth Green in "N.S.A. (No Snoops Allowed)".
In "Railroaded", he proposes roundabouts instead of Stan's bullet train idea to alleviate traffic. Stan promptly pours hot coffee on his head.