Never heard of him.
From reddit:
As far as who is Keith Nahigian:
http://nahigianstrategies.com/approach/
Runs Nahigian strategies, a PR firm. This may be a good move. Nahigian runs Terry McAuliffe’s (D-GOV-VA) PR as well; or at least used to. VA is a swing State and Hillary’s campaign manager was McAuliffe’s manager during his election.
Basically, Donald is stealing the other team’s playbook.