The Nomcom tend to chose individually brilliant individuals. This does not necessarily mean that the Nomcom deliberately assemble a team, they look at each position and try and put in the best expert they can noose.
What qualifications would you propose to the Nomcom to use in guiding their selection? As it stands it is not clear that the Nomcom would have a clear idea of what to do here (imho), and the results may be more of a surprise than a real step in the intended direction.
Frankly I'd suggest that if its an assistant chair (or vice-chair, etc) that is needed, then call it such, and proceed to work through how such a position can be established and filled, including how to phrase the position's required qualifications to the Nomcom.