What does Nick Carraway think of Jay Gatsby? How does his view of him change throughout the novel?

It varies. Nick first sees him making the grand gesture toward the heavens and is slightly ironic about Gatsby. Then he likes him when he meets him at the party, although he feels queasy about his connection with lowlife types like Wolfsheim as well as his obvious lies about some of his life ('What part of the Middle West?' 'San Francisco.'"). The ambivalent feelings continue until he sees that Gatsby remains true to his feelings for Daisy--especially just before Gatsby is murdered by George Wilson. In retrospect Gatsby comes for Carraway to stand for an American hero--noble, idealistic, and yet corrupt at the same time.