Oscar-winning actress Louise Fletcher, who played the iconic villain Nurse Ratched in "One Flew Over The Cuckoo's Nest," died from natural causes Friday in France, this according to her family.

Her son, Andrew Bick, tells TMZ ... Louise passed away peacefully in her sleep at her home in Montdurausee -- a commune in Southern France -- after she had overcome breast cancer several years ago.

Louise snagged the 1976 Best Actress Academy Award for her bone-chilling performance as Nurse Ratched in 'Cuckoo’s Nest.' The film, which swept all 5 Oscars in each of the major categories, centered around the tense relationship between Ratched and Randall McMurphy, a psych ward patient played by Jack Nicholson.

McMurphy was an anti-authority-free spirit who was a threat to Ratched's strict rules to keep the other patients in line. In the end, McMurphy won over the hearts and minds of the patients ... only to have a vengeful Ratched order him to be turned into a lobotomized vegetable.

The Nurse Ratched character was hand-picked as the fifth-greatest villain in movie history by the American Film Institute -- and she was runner-up to the Wicked Witch of the West as the greatest villainess.

After the success of 'Cuckoo's Nest,' Fletcher landed roles in other popular films and TV shows, such as "ER," "Picket Fences," "A Perfect Man," "Shameless" and "Star Trek: Deep Space Nine." She was nominated for an Emmy for "Fences."

Louise was 88.