What other novels relate closely to Fitzgerald's Tender is the Night?
So you have asked a question about what I consider (dare I say it?) my favorite book. Yes, that's right, an English teacher has declared a favorite. That being said, let's get to your question. While I'm not sure if I can name specific novels (if only because I feel that Tender is the Night is so strikingly unique) I can give you an idea of what kinds of comparisons you might tro to make between it and other novels.
I would draw on major themes in the novel, such as Nicole's mental illness and its effect on her relationship with her husband Dick. I would also consider how Nick's affair with Rosemary might have effected Nicole's mental illness. In addition, it is important to remember that at some point (in Switzerland I believe) Dick was Nicole's doctor. All of this raises important ethical questions that other books have surely addressed as well.
Something else to consider is that this is often considered a fictionalized autobiography of F. Scott Fitzgerald. There are a great many parallels between the Divers and the Fitzgeralds. Nicole Diver and Zelda Fitzgerald are quite alike, down to the psychological care they both received in Switzerland. Though unlike Nicole, Zelda never recovered.