Xenoblade Chronicles 2 - Button Challenge gameplay

ブレイドが必殺技を繰り出すと、「ボタンチャレンジ」が発生しますも。タイミング良くボタンを押せばダメージがアップ！
しかも成功すると、どこかから聞こえるナゾのナレーション（ボイス：利根健太朗さん）に、めちゃくちゃほめてもらえますも。悪い気はしないはずですも。 http://pic.twitter.com/1caaPMyOxc

— ゼノブレイド２ (@XenobladeJP) October 5, 2017

The following info comes from Perfectly Nintendo...

Monolith Soft. shared a video showcasing an element from the battle system called “Button Challenge” (official English name TBC). This occurs when a Blade uses a special move, and all you have to do is press the button with the right timing in order to increase the power of the move. You also get complimented by a mysterious narrator voice (voiced by Kentarou Tone in the Japanese version)., who shouts things like “Cool!” or “Excellent!!”.

from GoNintendo