The original question had to be edited. I would suggest that the theme of freedom and control is best embodied through the battle between McMurphy and Nurse Ratched. Both represent the freedom and control theme that drives the novel.
For Nurse Ratched, control is her defining characteristic. Her entire being is predicated upon control. Chief remarks on this with reference to clockwork as representing this notion of control:
So after the nurse gets her staff, efficiency locks the ward like a watchman's clock. Everything the guys think and say and do is all worked out months in advance, based on the little notes the nurse makes during the day. This is typed and fed into the machine I hear humming behind the steel door in the rear of the Nurses' Station.
In Nurse Ratched's world, all expression has been calculated. All understanding has been foreseen. Nothing is left to chance in how she runs the ward and how she views reality.
McMurphy is the element of freedom designed to disrupt Nurse Ratched's notion of control. In challenging "the way things are," McMurphy believes in freedom for freedom's sake. His challenge to the Nurse's ordered setting is one in which the battle between freedom and control is evident. His being is her opposite, and her presence seeks to be his negation. Their tug of war is an expression of each seeking to bring their own conception of reality into the ward. Nurse Ratched is able to silence McMurphy, but the ending is one in which the spirit of freedom has been revealed, forever altering a world of constant and perpetual control.