Two late goals from leading top scorer Victor Osimhen and Osinachi Ebere gave Nigeria victory over the Mexicans.
Nigeria had fallen behind in the 7th minute with Kevin Magana taking advantage of a defensive lapse.
Nwakali leveled up with a 25-yard free kick in the 35th minute and in the 43rd, Okonkwo finished beautifully to put Nigeria in the lead for the first time.
Mexico were back in the game again in the 60th minute through Diego Cortes’ solo run that saw him dribble past five players before slotting home.
Osinachi Ebere, however, restored the Eaglets’ lead seven minutes after and the tournament’s leading scorer, Victor Osimhen sealed the victory burying an 83rd minute penalty, after John Lazarus had been taken down in the Mexican penalty area.
With nine goals, Osimhen has now equaled Florent Pongolle and Souleymane Coulibaly’s record of most goals in a Under-17 World Cup tournament.
Nigeria is set for an all-African final against Mali on Sunday in Vina Del Mar. Mexico will face Belgium in the third place match.