Final answer:
The special thing about Nick's invitation to Gatsby's party is that he appears to be one of the few people formally invited, emphasizing the intention behind his attendance and setting the stage for his evolving relationship with Gatsby.
Step-by-step explanation:
What is special about Nick's invitation to Gatsby's party is that Nick seems to be one of only a few people actually invited to the party. Unlike many guests who likely just showed up, Nick received his invitation by special delivery from Gatsby's chauffeur, which indicated a level of intention and distinction from the otherwise haphazard attendance of the event. This detail is significant, as it subtly underscores the eventual relationship between Gatsby and Nick, and how Nick, serving as the novel's narrator, provides a unique perspective into Gatsby's world. Despite not being wealthy or famous, Nick's presence is deliberately sought out by Gatsby, which foreshadows their developing bond and Nick's growing involvement in Gatsby's life. F. Scott Fitzgerald uses this connection to not only drive the narrative but also to explore the nuanced social dynamics of the Roaring Twenties.