What are Nick's advantages in The Great Gatsby?

At the beginning of the story, Nick observes that his father once told him to be aware that others may not have shared the same advantages Nick had when he was growing up. This becomes significant later in the story because, of course, while Nick finds himself among people who have been far more privileged than he was, it transpires that Gatsby himself is one of those people who did not enjoy advantages when he was growing up.
The advantages referred to are, of course, the advantages afforded by a middle-class upbringing. Nick comes from a "well-to-do" family which has been important in their city for several years. They claim to be descended from aristocrats, although this is not true; they have a family-run hardware business, which ensures they have plenty of money and also means that the sons of the family can expect to receive employment in this business if they should wish to. Nick has also received a good education, and, although he had to participate in World War I, he knew that he would have a job to come back to afterward. All of these are advantages Gatsby did not have.

Nick outlines his advantages in the beginning of the book, noting that he comes from a well-to-do Midwestern family. This translates into money to offer him a comfortable life and good social connections. He is a Yale graduate and a friend of a very wealthy fellow Yale graduate, Tom Buchanan. He is immediately accepted in Tom and Daisy's upper-class circle (Daisy is his cousin). Tom, a racist, considers Nick a fellow "Nordic."
Because of his class background and educational advantages, Nick doesn't make the kind of mistakes that the lower-class Gatsby makes. Nick would never wear a pink suit or call people "old sport." Nick makes a joke to the reader of Gatsby's blunders such as his talking about big game hunting in Europe: people don't hunt tigers in Paris or Venice, as Nick satirically notes.
Nick is bankrolled for a year by his father so that he can go into the bond business, the kind of advantage Gatsby never had. While Tom accepts Nick as an equal, he sneers at and snubs Gatsby, treats him as déclassé, and implies he is not a "Nordic."