The council of Nicea was not even held in Rome.

It was held in Nicea, now in Turkey. And Constantine moved his capital to the new city of Constantinople, now called Istanbul. He did not believe the bishop of Rome was the head of the church. So it has nothing to do with Rome.
The council of Nicea made some bad decisions, but did not abandon the gospel. The bad decisions concerned matters not relevant to the gospel.
The churches of Corinth never considered the bishop of Rome as the infallible head of the church. They honored him, until the Roman church made innovations unacceptable to the Eastern church, so the split into Catholic church and Orthodox church happened. And the churches of Corinth followed the Orthodox church. Maybe now there is also a Catholic church in Corinth, but there might not be, Corinth is not a large city.
So what happened is the church of Corinth got divided into several congregations, most followed the errors of the council of Nicea, but did not abandon the gospel.