what is the combine? What is the relationship of Nurse Ratched, McMurphy, and the Chief to the Combine

The combine is the institution itself. In the "combine" all runs according to a set of rules that are never broken or questioned. Chief Bromden represents a cog in the machine. By following the rules, taking his meds and never questioning authority, he is set up as McMurphy's foil. Nurse Ratched is seen as a dictator and is a metaphor for oppression. She makes sure that all the cogs in the machine that is the institution keep running efficiently and without interruption. McMurphy is the one who fights against authority and oppression and represents freedom.

Ratched= oppressor/authority

Bromden= the oppressed/follower of authority

McMurphy= free thinker/freedom fighter/very anti-establishment