On 9 September 2009, Nevin guaranteed Ireland a historic sixth medal at the 2009 World Amateur Boxing Championships after he beat China's Yu Gu in Milan.

[3] At the 2011 World Boxing Championships in Baku, Azerbaijan, Nevin reached the semi-finals after beating Orzubek Shaymov of Uzbekistan 19–17 in the quarter's.

Nevin lost to Britain's Luke Campbell in the semi's through a very controversial countback, forcing him to settle for a second World Championship bronze medal.

[5] In his quarter-final bout he beat Oscar Valdez to secure a semi-final place and the guarantee of at least a bronze medal.

I've done everything I wanted to do in the amateur business, if I could change the colour of the Olympic medal I would but that's done and now it's time to move on and hopefully bring back a world title to Ireland."

[15] Nevin made his professional debut in a super featherweight bout on 17 March 2014 against Alberto Candelaria,[16] winning by unanimous decision.