I re-watched The Eyes of Tammy Faye recently and I'm sorry but I still think Chastain was a total hoot and a thoroughly deserved win, despite it being yet another celebrity impersonation.
Ranking the last ten Best Actress winners
Olivia Colman - The Favourite
Jessica Chastain - The Eyes of Tammy Faye
Frances McDormand - Nomadland
Frances McDormand - Three Billboards Outside Ebbing, Missouri
Cate Blanchett - Blue Jasmine (Tainted by Woody association but I need to re-watch as I do remember it being a bit of a tour de force)
Brie Larson - Room
Renee Zellweger - Judy
Julianne Moore - Still Alice (Love her, but this was the definition of a career win for a mediocre part)
Emma Stone - La La Land
Jennifer Lawrence - Silver Linings Playbook (Like her in other things, but this is an actively bad performance IMO)