I doubt she liked it initially as she does seem legitimately attentive to Youta when he got yeeted the first time and lost and arm and a leg. However, after she got yeeted things changed. The witches we know became witches when they got Kanejo's nano machine blood (which elicits another line of questioning, but it's tangential), so how exactly did Nina become a witch, hmmm?
Also if we view her actions under a Pro-Kanejo lens rather than a simple jealousy lens her vitriol at him copulating is connected to her potential belief these women are Kanejo's.