Why does Gatsby arrange for Nick to lunch with Jordan Baker?

Explanation:

Gatsby arranges for Nick to lunch with Jordan Baker in order to facilitate their romantic relationship and to provide Nick with an opportunity to gather information about Daisy Buchanan, whom is deeply infatuated with. By bringing Jordan and Nick together, Gatsby hopes to use Jordan as a bridge to reconnect with Daisy, as Jordan is a close friend of hers. Additionally, Gatsby believes that by having lunch with Jordan, Nick will become more acquainted with the intricate web of relationships surrounding Daisy, which may ultimately help Gatsby in his pursuit of winning her back.