Yep, this is basically fixed mindset vs. growth mindset. It's weird, Nagatoro was the one who initially scolded Naoto about how you can change what was you thought was predetermined, like his athletic ability. Yet we see Nagatoro thinking she can't change the outcome in beating an opponent she used to easily in the past because she saw someone do the exact same thing she scolded Naoto-senpai for refusing to acknowledge...?
Her way of thinking is wrong, I'm sure she knows it is wrong, and I think senpai may call her out on her hypocrisy.