The win means Nigeria takes sole possession as the most successful team in the competition's history with four wins, denying Mexico the chance to win its second consecutive title and third overall at the U-17 level.
Mexico had hoped to get off to a strong start after being thumped 6-1 by the Golden Eaglets in their opening match. That hope was fleeting just nine minutes after the whistle when Nigeria had a three-on-one break. Defender Erik Aguirre tried to stop a low cross that would've led to a Nigera tap-in, but he ended up putting it in himself for an own goal.
Mexico tried to settle and made it into the halftime break without allowing another Nigeria goal, though frustrations were clearly building. The second half didn't bring better luck for Mexico, with goalkeeper Raul Gudino deflecting a Musa Muhammed cross directly into the path of Kelechi Iheanacho, who had no problem sliding in the second goal.
Nigeria needed no such luck for its third, as Muhammed curled in a beautiful free kick into Gudino's net. The keeper had little chance to stop the right-footed effort.
Mexico had advanced to the final by stomping Argentina 3-0 after a thrilling win against Brazil in the quarterfinals. That match finished 1-1, and Mexico took it 11-10 in penalties. Earlier Friday, Sweden won the third-place match, meaning the tournament's medal winners all advanced from Group F.