Per the Google
"In the first-round of each regional tournament, the home team will be the higher seed. In subsequent games, the home team shall be determined according to the following formula: 1. The institution that has been the home team the fewer number of times shall be designated the home team. If both teams have been the home team the same number of times, it kicks to a tiebreaker awarded to whichever team has been the visiting team more often."
Personally, I would change it to "the higher seed is the home team," but that makes too much sense for the NCAA.