A nominating committee is elected by the process written in your unit bylaws under article VII, Section 3.  It tells you the number of members to be elected and from which body they should be elected.  In other words, a specific number is elected from the executive board from its members and a specific number is elected from the unit members (not on the board) at a regular unit meeting. The nominating committee for your unit should be in place at least 60 days before the election of officers. It is actually a good idea to elect your nominating committee at the beginning of the school year so they will already be in place when it time to pick a slate of officers for the next year.
 
The bylaws also explain how the committee chair is elected and when the committee report to the unit is presented for a vote; there is other information as well.

While names for chairmen may surface while the nominating committee is looking for members to serve as officers, the committee is only responsible for the officers' slate.  Be aware that the unit president may not serve on this committee.
 
Please refer to your unit bylaws to determine the make-up of your nominating committee.  Section 7 in the NYS PTA Resource Guide will give you further guidance in this area.