Ex- African Footballer of the Year the Napoli star helped Nigeria build a commanding advantage, before they were compelled to hold on for a narrow win.
The three-time champions weathered a dramatic comeback attempt from Tunisia to advance to the knockout stage of the Afcon tournament taking place in the host nation.
Jose Peseiro's side seemed to be cruising in their pool clash in the Moroccan city, enjoying a three-goal cushion with only 17 minutes remaining courtesy of goals from their attacking trio.
Yet, Montassar Talbi reduced the deficit with a powerful header from a Manchester United midfielder set-piece, sparking hopes of a recovery.
The drama escalated when the North Africans were awarded a late penalty after a VAR review identified a handball by Bright Osayi-Samuel. The left-back converted in the 87th minute to create a nail-biting finale.
The Carthage Eagles came agonizingly close from a last-gasp equalizer in stoppage time, with captain Ferjani Sassi heading a opportunity narrowly wide before a substitute guided a half-volley past the goal frame.
This result means that the Super Eagles, champions of the tournament on three previous occasions, advance to six group points and are guaranteed first place in their pool with a match still to be contested.
In the next round, they will meet a best third-place side from one of the other preliminary groups.
Meanwhile, the 2004 champions stay on three group points, with the East African teams locked on a single point after playing out a 1-1 stalemate in the day's other fixture.
The final pool matches will see the group leaders stay in the city to take on the Cranes on the next matchday, while the Eagles of Carthage travel back to Rabat to face Tanzania.
Ali Abdi smashed the ball from 12 yards to offer his team a glimmer of hope of snatching a draw.
The Super Eagles, runners-up in the previous edition, become the next team after Egypt to reach the next phase, but coach Eric Chelle and fans will undoubtedly be breathing a sigh of relief.
What looked like set to be a straightforward final quarter transformed into a nerve-wracking affair.
The prolific striker had a effort ruled out for an infringement before opening the scoring right before the interval, expertly guiding a header into the far post from an Atalanta winger cross.
The advantage was extended early in the second half when the Leicester City midfielder rose highest to power home a header from a Lookman kick.
Osimhen then turned provider Lookman for the seemingly decisive goal, only for the defender to steer a header past goalkeeper Stanley Nwabali to begin the comeback.
The key incident came when a high ball hit the forearm of Bright Osayi-Samuel, with referee Boubou Traore pointing to the spot after consulting the VAR monitor.
Although Ali Abdi's successful penalty, Tunisia in the end fell short of pulling off a stirring recovery.
Tunisia's destiny remains in their own hands; a point against Tanzania will be sufficient to see them through, and manager Sami Trabelsi will be eager to avoid a recurrence of the 2013 early elimination that led to his departure.
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