Ahmed Musa scored a brace in the second half to take Nigeria to second in the Group D standings, behind Croatia who already qualified in the top 16.
BBC Sports reports, after a goalless first half, Musa gave the African nation the lead with a counter-attacking goal early in the 49th minute and increased the lead with a brilliant solo goal in the 75th minute.
Iceland missed a late penalty – awarded after a video assistant referee review – when Gylfi Sigurdsson fired over.
Article continues after advertisement
Victory over Nigeria in their final game would see Argentina safely into the last 16 – as long as Iceland does not beat group leaders Croatia.
Advertisement