Campbell operated smoothly in the first round, applying pressure cleverly and pumping a string of lefts into the Irishman's face.
Nevin replied strongly in the second, cutting the gap to just one point as they entered the third round.
Both men were well into their stride by the final round and were both landing shots.
The referee gave Nevin a count after he was adjudged to have been downed by a shot from Campbell, however it looked like more of a slip.
That gave Campbell an added point to his total and it was he who was finishing strongly.
It was a tense finish as both men felt that they had done enough to win, but it was the Brit who claimed a 14-11 decision.