Similar to Connecticut, Maryland, Mississippi, Nebraska, New Mexico, Oregon, Tennessee and Wisconsin
North Carolina's state board of Elections determine which candidates are "generally advocated and recognized in the news media throughout the United States or in North Carolina" as a presidential candidate.
A candidate may also petition the Elections Board with 10,000 signatures signed by citizens whom are registered to vote as "affiliated" with the respective party, in this case, Republican.
North Carolina holds semi-closed primaries, which means “In a partisan primary, voters who are affiliated with a political party may only vote the partisan ballot for the party for which they are affiliated; they are closed from voting in another party’s primary. Unaffiliated voters may vote in any one recognized party’s primary.”
The Primary is scheduled for March 3, 2020