I just got an S with nunu and got no chest. On my profile it says that I can get a chest for S- or better, but I did not get the chest.
[sg-shisa]
Gilgayu3 votesYou can only get 1 chest per champion per season.
If you already got a chest from nunu this season, then you can't get another one.
You can check which champions you got chest from already by going into your collection, and the champions with special boarders are the ones you already earned chest with.
Hethalean2 votesWhat does this show
wolf jade1 voteshttp://prntscr.com/m1m9z6 check here
2311 voteshttps://gyazo.com/e54c49a629cfd6cc08deb53df8afbd12 it shows that I can get a chest
wolf jade1 votesclick on it.
Hethalean1 voteshttps://gyazo.com/e54c49a629cfd6cc08deb53df8afbd12 it shows that I can get a chest
Mouse over it, and show us the timestamp on when the next comes up. It could be that you have one now, but had 0 for that game.