It's hilarious that Nino is acting so indignant and bitchy when she is the reason that Fuutarou is even still around after she fooled her father and conned him into thinking that they all passed.
Miku, Itsuki, Ichika, Yotsuba... none of them immediately tried to save/keep Fuutarou as their tutor. Now she's done a 180 and is actively trying to get rid of him to the point of getting into slap fights with her sisters and running away.
...The only thing that changed during that time that makes me think she would be okay with suddenly turning on Fuutarou... is the fact that there is an alternative. And isn't it interesting Nino mentioned rather having that alternative (which doesn't actually exist... since Kintarou is obviously Fuutarou) than him in this chapter? Oh... Fuutarou... please put this spoiled bitch in her place by crushing her dreams of a hot bad boy coming to take her away, only to pull off the wig and show her that the studying freak dragged her back to a tutoring session. Please, please show me that. Please.