The three-time African champions showed their strength in depth to outclass their spirited opponents with two second-half goals
Nigeria's quality proved to be a bit too much for Guinea-Bissau to handle, as goals from Umar Sadiq and William Troost-Ekong helped the Super Eagles shoot down the Wild Dogs
The Eagles had qualified and sealed the top spot in Group D even before kickoff, but their West African neighbours needed all three points to stand a chance of qualifying.
Head coach Augustine Eguavoen made significant changes to the first eleven that had outplayed Egypt and Sudan, with Semi Ajayi, Umar Sadiq, and Kelechi Nwakali starting from kickoff.
Still, the 2013 Afcon kings were in no mood to hand gifts to the Djurtus and duly dispatched their opponents courtesy of two well-taken goals.
How it happened
A cagey opening quarter of an hour burst to life when Iheanacho made space for himself with a delicate piece of skill. But just when the Leicester City man was about to strike, he was bundled off the ball. The referee, however, ignored the Nigerians' appeal for a penalty.
Moments later, Semi Ajayi nodded just over from a lovely free-kick delivered into the box by Kelechi Nwakali.
And the Eagles surely should have opened the scoring in the 24th minute, but Sadiq somehow managed to get the ball tangled between his legs after going past the goalkeeper following good work from Nwakali.
Nigeria came close again on the half-hour mark when another pinpoint Nwakali corner found Iheanacho alone at the back post, but the goalkeeper made a comfortable save from the striker's half volley.
Guinea-Bissau grew into the encounter and had the last real chance of the half, but Jorginho sent his effort wide after Nigeria failed to clear a corner kick properly.
But the Super Eagles seized the initiative after the break and soon took the lead off the boot of Sadiq. Iheanacho did brilliantly to send a low cross across goal, leaving the Almeria striker with the simple task of tapping it into the net and atoning for his first-half miss.
Still, Eguavoen withdrew the goalscorer and Ejuke seconds later, with Slavia Prague's ace Peter Olayinka and star man Moses Simon replacing the duo.
It became the Moses Simon show from that moment on, with the Nantes forward showing on several occasions why he is one of the leading contenders for the Most Valuable Player of this championship.
The Eagles were not satisfied with the narrow lead and they continued to attack in number with their best chances coming from the left flank. One of those chances fell to Iwobi after a brilliant interplay with the tricky Simon, but the Everton man's shot was blocked.
Nigeria eventually got the second goal they deserved, albeit after a lengthy VAR review, with Troost-Ekong applying the finish after an excellent Simon shot came back off the post.
That goal was all Simon, though, with the 26-year-old dribbling past three Wild Dogs before striking at goal with venom.
Uzoho pulled off two decent saves at the end, but the result was never in doubt as the Super Eagles marched on with their perfect record intact.
What comes next
Three wins out of three take Nigeria to nine points, confirming their superiority in a group that had three former champions of the competition.
The Super Eagles next opponent is yet to be decided, but it will be one of the teams that finished as the best third-placed sides.
All I’ve got to say is ‘well done super eagles’. Simon Moses is from another planet. AFCON MVP loading…..