This was such an awkwardly made battle.
The mere fact Nanu forces Ash to fight on a 3-on-1 is just weird. At first I thought Sunny D-roc would go through it all in one go, but the meaning is lost when Tapu Bulu just...gives him a Sitrus Berry before the final bout. So, wait, can trainers really use items before or during a match? The rules aren't just explained in full in the anime.
Either Sunny D-roc has a lot of strength, or Nanu's team is made up of frail mons. I swear Sunny D-roc is starting to become the Alolan ace for Ash.
Nanu apparently acted "like a Dark-type trainer would," but, that's subjective, because we haven't seen Dark-type only trainers act like that. In fact, I'd say he acted TOO much into his role, so much that he takes the "Brilliant but Lazy" trope to an extreme with the "brilliant" part.
Nanu: Here's a Darkinium Z...but you're not suited for it.
Ash: B-But I had a Greninj-
Nanu: That's soooooo 2013. Here, have a Z-Crystal that I so conveniently happen to have for your unique dog.
anime!Nanu isn't as interesting as game!Nanu is. anime!Nanu puts more effort into his stuff and smiles way more often than the precious moments game!Nanu has (then again, anime!Cyrus had a waaaaaaaaaaaaaaay sunnier disposition than game!Cyrus, which makes me believe the anime staff doesn't do well around stoic characters).
Can't wait to see how they represent Hapu. Given she's a girl, I'm so expecting a Hapu arc ala Korrina arc.