Not enough Ancient Greek what-ifs. So what if Athens maintains hegemony in Greece?
Depends on the PoD and what you mean by hegemony. There's two scenarios that come to mind: one in which there is a decisive victory and the other in which there's a more limited one.
For a decisive win, there's a few PoDs. Maybe a domino series of victories starting with Nicias having a slight case of dead and Alcibiades getting his light version of the Sicilian expedition and accomplishing his objectives with it. The Athenian losses OTL are avoided, Syracuse gets beaten down, and the balance of power shifts more heavily towards Athens.
It's a late-game win, Athens is hurting, but maybe they really become hegemon. You'll at the very least avoid OTL's coups.
I don't know that it would be much more than a pyrrhic victory, though. When Athens collapsed and the Spartans defanged them, they technically "won". They were so exhausted, though, that their own force projection was hurting afterward. Athens might win at the cost of losing their hegemony as well.
There's the possibility of a more limited win, though.
One scenario might be that if Brasidas doesn't hold at Amphipolis, you could see both Sparta and Athens retiring from the field in good shape. Cleon holds onto power longer (died at Amphipolis) and there's a stronger overall Athenian position prior to the next round of peace talks. With their stronger position, Athens look conciliatory without going status quo ante bellum and maybe the peace can hold.