Nigeria opened scoring in the 19th minute through Ighalo off a Kenneth Omeruo assist to get the team off the block after the morale crushing 2-0 defeat to Madagascar.
However, Cameroon responded in kind with two quick fire goals before the interval.
Stephane Bahoken punished the Eagles defence after they switched off allowing Christian Bassogog while Omeruo was ball watching.
Three minutes later, Clinton N’Jie beat Daniel Akpeyi to his near post as he held off a challenge by Ola Aina.
Botswanian Referee Joshua Bondo blew the whistle for half-time and Nigeria were staring down the barrel of the gun and elimination.
The tables turned quickly and the Nigeria Coach knew the team had to come back with a response of their own and perhaps the team talk in the locker room was about how playing with heart, creating more chances and putting them away.
In the second half, Gernot Rohr made his first change; just past the hour mark, introducing Samuel Chukwueze for Simon Moses.
That decision proved to be productive as the 20 year-old’s pace and whizzing dribbles unsettled the Cameroon defence.
Two minutes after that change Ighalo grabbed his second of the game and third of the competition feeding off a chest down assist from Ahmed Musa.
Cameroon had not conceded a goal in the competition before Saturday’s game and Andre Onana had been solid in goal.
But here after 63 minutes his goal had been breached twice and three minutes after the second, Alex Iwobi buried what proved the decider.
Iwobi himself had not scored in a competitive game for Nigeria since October 2017, and his next couldn’t have come at a better time.
A sublime nutmeg by Ighalo to lay the ball in the path of the unmarked midfielder who only needed to stab the ball past Onana, didn’t disappoint.
The win saw Nigeria progress to the quarter-final for the 15th time in 18 appearances in the competition.
For the Super Eagles Head Coach it is also his first time he has guided a team to the quarter-final of the competition after reaching the round of 16 in 2015 with Gabon.
Nigeria will now face either host Egypt or 1996 winners South Africa in the quarter-final on July 10 at the Cairo International Stadium.