Nigeria beat Guinea-Bissau 2-0 in Garoua to become the only side at the Africa Cup of Nations to win all three group games.
After making eight changes to the side that beat Sudan to seal their last-16 place, Nigeria took time to warm up.
Umar Sadiq opened the scoring shortly after the break following a cross from striker partner Kelechi Iheanacho.
Captain William Troost-Ekong sealed the win after tapping into an empty net after fine work by Moses Simon.