Thanks to Pokebank, I was able to transfer my Hyper Voice Hidden Ability Eevee over named みらい (栗山未来) over and evolve it to Ninfia. Of course after a few tries at the Battle Testing, I manage to have a perfect run. This is the moveset I used:
Modest Ninfia @ Leftovers (たべのこし)
252 SP Atk, 48 HP, 208 Def
Calm Mind (めいそう)
Hyper Voice (ハイパーボイス) – Black 2/White 2 Tutor Move
It managed this:
Yep, it can be considered slightly overpowered, once you get some Calm Minds in.