Best practice usually suggests collecting nominee names, and then a committee can take various paths to determining who is ultimately on the ballot.
The best election practices start well before the nominee process, and includes pulling in new people to projects and committee work, and those who are successful contributors should be asked to consider more participation as well as possibliy running for a Board position in the future, etc.
Willingness, a record of follow through, commitment to the organization, ability to work well with others, and thoughtfulness are all good indicators of a potential successful Board member.
Here is a good article regarding building a good Board/ballot.
https://www.boardeffect.com/blog/board-member-election-process/
Attached are the policies the ACBS Board follows in building the ballot.