We are being asked to write an argumentative essay that assesses a literary critic's analysis of One Flew Over the Cuckoo's Nest. Can you suggest a place to look for some well written essays on the novel?
As an English professor myself, my sense is that what your instructor means by "literary criticism" isn't just a well-written essay, but what scholars call a "peer-reviewed" essay, meaning one that has appeared in an academic journal that has all essays submitted for publication read not only by the editor but by two other scholars in the field.
The main place to locate peer-reviewed essays is the MLA International Bibliography. You should have free access to this through your university library's website. Not only can you search for articles, but usually you can pull up full-text versions with a single click. Also available from most university library websites is JStor, a database that contains a huge inventory of articles from past issues of journals.
If you don't have access to a university library, another possibility is Google Scholar. This isn't the regular version of Google; you need to start your search from:
However, it does have the same search interface as Google. Even better, you can easily restrict your search to articles published after 2011.
One major area of recent scholarship on the novel is within disability studies, a branch of criticism that looks at how cultures portray and respond to disabilities. The journal Disability Studies Quarterly has several relevant articles, including "Disability and Gender in Ken Kesey's One Flew Over the Cuckoo's Nest" by Leach and Murray. Another possibility is:
Benjamin Goluboff, "The Carnival Artist in The Cuckoo's Nest." Northwest Review 29.3 (1991): 109-122.