Kenneth Samuel Wuest holds that all three original New Testament verses' usages reflect a derisive element in the term Christian to refer to followers of Christ who did not acknowledge the emperor of Rome. The city of Antioch, where someone gave them the name Christians, had a reputation for coming up with such nicknames. However Peter's apparent endorsement of the term led to its being preferred over "Nazarenes" and the term Christianoi from 1 Peter becomes the standard term in the Early Church Fathers from Ignatius and Polycarp onwards.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Because Christianoi endorsed it, which term was preferred  over Nazarenes?
unanswerable