Toddler trouble at the nursery

My eldest is two and a half and she goes to nursery three days a week. There’s another girl at the nursery, around the same age as her, who seems to have some issues with hitting. Let’s call her Amy (not real name). We know Amy hit my daughter a few months back. Nursery were spoken to, they said they’d monitor and teach kind hands etc. Since then we’ve heard grumbling at the nursery gate about Amy that suggest she’s still causing trouble, but nothing that affected my daughter.

Yesterday my daughter told us “Amy hit me” in a heartbreaking little voice, but we got no more useful information out of her. My wife raised it with the nursery this morning, and was told that Amy had hit another child, and they were continuing to work on her. And yeah, fair enough, my toddler (and many others, I suspect) doesn’t have the consistency of language to differentiate between “I was hit” and “I saw someone else hit”, so maybe it’s communication thing. But this Amy obviously has some issues.

I’m a bit lost as to what to do. We’ve told our daughter to loudly say “no” and tell an adult if someone is mean to her. And I know that kids who hit are likely to have problems at home and so I don’t want to teach my daughter to be a mean girl in return. But this behaviour is obviously getting to her, and I just want my little girl to feel safe and happy.

I don’t know if we can ask the nursery to do much more, the staff are aware and keep an eye out, but they can’t be omniscient. And she has friends there, so I don’t really want to move nurseries. Does anyone have any ideas?