Nairo didn't get any grab confirms on Mr. R outside of fair followups. When he went for uair his spacing was always off and he'd whiff.
The one uair uair up b he had, he used side b by accident and the commentators thought he side B'd on purpose. It wasn't going to kill anyway.
There are only a few select times where ZSS should be getting kills with uair (uair) up b. But the assumption from viewers and most commentators is that a ZSS getting a grab at 35 means the player needs to ladder combo and the ladder combo is supposed to kill from ground level, and when it doesn't they say something about nerfs despite the fact that that didn't even kill in 2015 (but such is the world of 98% of people not knowing how ZSS jank works).
ZSS players for a long time needed to start converting fairs, bairs, and uair fairs off of grab and use less up b. It keeps uair fresh and gives ZSS stage control that she can't get when she ends a combo with up b. Nairo and Marss have gotten better about that. ZSS players get the vast majority of their kills off of up b oos and bair anyway, not ladder combos, nair flip kick, etc.
Game one Mr. R vs Nairo they both played extremely high level Smash that's typical of their sets, but after that Nairo stopped adapting. Always dsmashing at the ledge and getting hit by either bf or the wind hitbox on vanish, flip kicking into the stage out of pressure when Mr. R was scouting for uairs on that from the beginning, etc.
I was predicting Mr. R to win this set either way.