The News Agency of Nigeria (NAN) reports that the Super Eagles, who played later in the day in Group L, qualified by virtue of the result of the earlier fixture.
Lesotho hosted Sierra Leone in the earlier fixture at the Setsoto Stadium in Maseru, drawing 0-0.
This meant table-toppers Nigeria with eight points have secured their 2021 AFCON ticket, while Benin Republic with seven points can also ensure qualification.
Sierra Leone, with four points, occupied the third spot on the log.
Nigeria’s victory over Benin Republic will give the Leone Stars a slim hope of qualification heading into their penultimate round fixture.
The Leone Stars hosst the Squirrels at the National Stadium in Freetown, on Tuesday.
Bottom-placed Lesotho with three points are out of the race and will be playing for pride against the Super Eagles at the Teslim Balogun Stadium in Lagos, also on Tuesday.
GROUP L P W D L Pts
- Nigeria 4 2 2 0 8
- Benin 4 2 1 1 7
- Sierra Leone 5 0 4 1 4
- Lesotho 5 0 3 2 3