He becomes at effect His Grace Frank Nubuasah, Bishop of the Diocese of Gaborone .
The Appointment made by Pope Francis is one of “Archbishop ad personam”.

The rank of Archbishop ad personam is conferred on some bishops who are not Bishops of an archdiocese.
They hold the rank, not because of the see that they head but because it has been granted to them personally (ad personam). Thus the Diocese of Gaborone remains a Diocese.
Congratulations Your Grace.