The National Board slate is determined by the National Board Development Committee.* Current information about how to nominate someone for the National Board of Directors could not be found on the GSUSA website. However, here is a referral form from 2016: Candidate Referral Form. For more questions, it’s recommended to email BoardOffice@girlscouts.org and ask for more information.
*Source: Constitution/ARTICLE XII/NATIONAL BOARD DEVELOPMENT COMMITTEE, NOMINATIONS, AND ELECTIONS/SINGLE SLATE OF NOMINEES 9.