Argentina don't play Nigeria until the last game, by which time a point might be enough each for Iceland and Croatia to go through.
Next round of games is Iceland v Nigeria and Croatia Vs Argentina.
I expect Iceland to be on 4 points after that, and I genuinely think Croatia are an all round better team than Argentina so would have them as slight favourites for the win.
I presume if 3 teams finish on 5 points (Argentina Croatia draw, Croatia Iceland draw and everybody beets Nigeria) it just goes to goal difference, so basically whoever scores the most against Nigeria?