It's possible. With Francis it's always possible. Even if he doesn't get the KO there's the possibility of a doctor's stoppage—if that swelled eye Stipe got in the 1st round had gotten any worse...
But —
1. We can't be certain that Ngannou's made improvements to his game (because he's had little time to show it while he's been knocking out foos just like he did before he met Stipe.)
2. Even if he has made improvements we can't be sure if they are the really needful ones. For example, a lot of people have pointed out how Ngannou was aggressively headhunting Stipe in a most uncharacteristic manner, and that this time he'd surely be more patient and not gas as fast. BUT all the good intentions in the world won't matter if Francis hasn't learned how not to bite on feints. If he hasn't, Stipe can fool him into overswinging just the same way.
3. Knocking Stipe seems to depend a lot on his inattention or an element of surprise. DC KO'd him with a short tight shot exiting a clinch, a punch he couldn't see coming. But Francis isn't exactly a subtle thrower. His looping punches can be much more easily read than DC's faster ones.
BTW I really don't understand why people are saying stipe looked bad in the last DC fight. We already knew DC had the faster hand speed, what exactly were you expecting? And Stipe dominating DC in the clinch—DC's bread and butter!—is actually damn impressive.
Ngannou's most typical KO punch is not the type he used against Rozenstruik - its usually the counter hook or uppercut that he is very good at timing his opponent with.