A postitive declaration of Nullity ( where the Sacrament has been found to be invalid or null) , per Canon Law, have to be ratified by a designated Court of Appeal (ocalled a Tribunal of Second Instance).
This is true everywhere and is required by Canon Law
Can. 1438 Without prejudice to the prescript of ⇒ can. 1444, §1, n. 1:
1/ from the tribunal of a suffragan bishop, appeal is made to the metropolitan tribunal, without prejudice to the prescript of ⇒ can. 1439;
2/ in cases tried in first instance before the metropolitan, appeal is made to the tribunal which the metropolitan has designated in a stable manner with the approval of the Apostolic See;
This is often done at the Metropolitan level ( Archdiocese).
But of the Metropolitan Archbishop has designatated a national tribunal, that is certainly within his power to do so.
If a positive result is confirmed by the Court of Appeal, either party has a right to appeal further to Rome.