Jessica Chastain or Bryce Dallas Howard
No question about Octavia Spencer being nominated for Best Supporting Actress (and eventually winning it).
But if there should be another nomination from this film in the same category, I think Bryce Dallas Howard should have got it instead of Jessica Chastain. Don't get me wrong, I loved Chastain in this movie as much as I loved Howard and I know that a character like Celia is not as easy to play as it looks like.
But I think Howard's performance had that little bit more of strength. Her simply being present on screen is enough to exhude all her character's mean-willness and hatred, even before doing or saying any atrocity.