Ever since Nick became aware of Carol, he's been aware that she doesn't really consider herself as an Earthling, and has a bunch of stuff to do all across the galaxy. This is why he started the Avenger Initiative: to find other people capable of defending Earth when she can't, or won't. (For example, when the Chitauri invade, or when Ultron tries to wipe out humanity.)

That's exactly what he's doing (or, as it turns out in the post-credits scene, [delegating](https://en.wikipedia.org/wiki/Spider-Man:_Far_From_Home#Plot)) in *Far From Home*. Tony, Cap and Nat are gone, Thor's off being a hippy space pirate, Bruce is probably busy taking selfies, Hawkeye's probably retired.

Nick might think there's a risk that Peter might give up the whole hero thing after his mentor died. But he definitely knows that there are plenty of threats to <del>Disney cinema grosses</del> Earth, all over the <del>release schedule</del> galaxy, and that any potential heroes on Earth need to step up and <del>show they can compete with Aquaman 2</del> get in the game.