Who is telling the story to the reader? In other words, who is the narrator?

The narrator in the novel One Flew Over the Cuckoo's Nestis "Chief" Bromden, a Native American patient who has been in the asylum for his schizophrenia longer than any of the other patients. In many ways, Chief acts as a foil (or a character with opposite characteristics from the protagonist) for the protagonist of the story, Randle McMurphy. McMurphy is new to the asylum, while Chief has been there for a long time. This...

The narrator in the novel One Flew Over the Cuckoo's Nest is "Chief" Bromden, a Native American patient who has been in the asylum for his schizophrenia longer than any of the other patients. In many ways, Chief acts as a foil (or a character with opposite characteristics from the protagonist) for the protagonist of the story, Randle McMurphy. McMurphy is new to the asylum, while Chief has been there for a long time. This gives the two opposing perspectives; while McMurphy is like the new kid in school, pushing boundaries to see how far he can go, Chief knows the lay of the land better. This can be a hindrance to Chief, however, as he also seems resigned to living the rest of his life in the asylum. 

The characters act as foils for one another based on their personality traits as well. While Chief has pretended to be deaf and mute for years (the better to quietly observe the asylum and stay out of people's way), McMurphy is outgoing, loud, and extroverted.

The main characteristic the two characters share is their intelligence. Chief makes such an excellent narrator because his years of quiet observation have led to numerous insights about the world of the asylum. Having McMurphy front and center of the action, though, allows the readers to engage with that system and learn while McMurphy is learning how it all works and how it can and cannot be disrupted.