The actress is up for an Academy Award for her role as CIA agent Maya, who spends almost a decade tracking down terrorist leader Osama bin Laden.
Chastain admits she has been overwhelmed by Zero Dark Thirty's critical acclaim, and hopes its success paves the way for more movies about strong leading ladies.
She tells the BBC, "For a long time I was hearing that studios didn't want to make films with female leads because they didn't think they would make any money. Maybe this is showing a new trend - audiences are interested in everyone's story, not just the story of the few...
"It's very rare to play a character defined by her work and not her male counterpart. I think it represents this generation of women who are independent and capable and strong and not the product of something else - the girlfriend or the victim of the villain of the piece. It's really exciting to play a woman who's smart and intelligent and who uses her brain."
Director Kathryn Bigelow agrees, adding, "As we began digging into this story, I realised there were a lot of stats (statistics) about how many women there are in the intelligence community. The fact it was a woman was fascinating to me."