He could meet some old enemies who have changed their ways. For instance, some of Orochimaru's former minions might have decided to start anew and cross paths with Naruto. Or perhaps he meets a hermit ninja who has been living in isolation for years and imparts some valuable wisdom to him.
Naruto might encounter other Jinchuriki. Since he is a Jinchuriki himself, meeting others could lead to interesting exchanges. They could share their experiences of living with a tailed beast. It could also lead to a new alliance or a new understanding between different villages that have Jinchuriki among their ranks. Another possibility is that he meets some wandering ninjas who have unique skills and abilities that Naruto has never seen before.
There's a chance that Naruto meets some of the previous Hokage in a spiritual or mystical way during his journey back. They could give him advice on how to lead the village in the future. He may also meet some young ninjas from other villages who are on their own training trips. This could lead to friendly competitions and exchanges of ninja knowledge between them.
Chapter 738, "Here to Fight!", is the clearest early answer because the buildup finally cashes out in a real clash. The setup is Feeling that something was amiss, he immediately called Jiang Li., but the pressure keeps building through Sister Li, don't you know how to divine?.
Chapter 884, "Master?!", is the clearest early answer because it turns Shuiyun Temple's situation into a concrete plot event. Early on, I've heard this temple is quite magical, but why are there so many.... By the end, After all, Master often goes on retreats, leaving the teaching to the....
A practical answer is Chapter 9, because it turns the idea into a concrete scene. The chapter opens with Exactly, the Qiao Family isn't that great either., adds pressure through Since it was for the Jiang Family's welfare, then as the matriarch, she..., and ends on Qiao, unable to save face.
Chapter 734, "Are These Primary School Students Arguing?", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. The chapter gives readers a real answer by opening on Old Sir Jiang was especially happy.
If you want the clearest chapter reference, go to Chapter 1. Early on, Jiang Li, I'm warning you, don't set your sights on Yinwan anymore, or...; later, the chapter leans on Following a bout of tinnitus, she struggled to open her eyes and finally....
Chapter 939, "When Did the River Moon First Illuminate People? [Extra · River Moon Chapter]", is the clearest early answer because it turns Seeing Jiang Yan's situation into a concrete plot event. It opens with Using food to win over Shang Shuyue really works.
Chapter 682, "Too Conspicuous to Keep Around", is the clearest early answer because it turns Ye Chu's situation into a concrete plot event.
Chapter 924, "Competing to Auction Themselves", is the clearest early answer because it turns Jing University's situation into a concrete plot event. The chapter turns that into something concrete by moving from Not only did the netizens feel like they were on a roller coaster,...