Big Nurse is in charge of the whole ward and she makes sure everyone is aware of that. She clearly reigns over all of the attendants and even the Doctor; while in most hospitals, the Doctor is in more control than any of the nurses.
"Then... she sights those black boys. They're still down there together, mumbling to one another. They didn't hear her come on the ward. They sense she's glaring at them now, but it's too late. ... She goes into a crouch and advances on where they're trapped in a huddle at the end of the corridor. ..She's going to tear the black bastards limb from limb, she's so furious (Kesey 10,11).
The way that even her staff are terrified of simply her presence, shows that she can instill fear in anyone on her ward.
McMurphy on the other hand, has one thing that sets him apart from the other patients, he's confident. He may also have the fact that he's not crazy, but his confidence in himself sets him apart from the rest. Referring to the third paragraph, in it's entirety on page 84, it truly shows that everyone not only sees the difference, but has accepted it. When Big Nurse is after McMurphy for brushing his teeth, singing, and any other rules he was breaking, you could start to see her "machine" like qualities start to break down.
"Her lips are parted., and her smile's going out before her like a radiator grill, I can smell the hot oil and magneto when she goes past. ...Then as she's rolling along at her biggest and meanest, McMurphy steps out of the latrine door right in front of her, holding a towel around his hips --stops her dead!" (Kesey 87)
McMurphy is turning out to be quite a force to be reckoned with on this ward, and he wont let Big Nurse, or anyone else for that matter, forget it.
In the end of the novel, some may say that Big Nurse has won, because she ended up indirectly killing McMurphy, by performing a lobotomy, however, I feel like this is when Mac triumphs the most. Like in one of my favorite movies, and also spoken by Babe Ruth "Heroes get remembered, but legends never die (Sandlot 1993). A hero is only remembered by those whom he or she has touched, but a legend's story is passed on through years and years of retelling. Mac is a legend because he used himself as a martyr for these people who he barely knew coming into this. Big Nurse lost because she couldn't do her job and control this man, she had to rely on using a machine because she wasn't strong enough to take down the force that was McMurphy.