But the agency stressed the appointments were new roles, and had been made before the defection of Jon Williams and Nick Stewart to Beattie McGuinness Bungay (Campaign, 26 January).
Ormerod has joined as the managing director for digital. He was previously the group account director at AKQA.
Nunn has left his role as a managing partner at WWAV Rapp Collins to become the regional managing director for HTW's Samsung and Scottish Courage accounts.
The appointments have been made by John Butler, who has been the chief executive of HTW for six months.
Butler said: "We believe our digital capabilities are second to none, and we want to exploit all those abilities in the service of our clients. Richard and Julian will be instrumental in this."