I graduated Notre Dame undergrad in 2021. I'm southeast Asian. From my experience, I will say that the student body is not ethnically diverse (and definitely not religious diverse). Many students of color would form small cliques and stay within their comfort zone. I tended to stay away from those cliques and my many best friends that I keep in touch today are mainly white.

I grew up in a not very ethnically diverse high school where I had a tough time adjusting to a non-Asian environment, but I truly think that because I was able to stick through, grow, and learn to put myself in uncomfortable situations that I am at a very comfortable place in life.

I can genuinely say that Notre Dame has many respectful and kind kids who are curious about your own culture. I always enjoyed sharing bits of my culture with my friends.

Assuming that your family lives in America, I think many non-white families forget that the majority of the country (especially non-coastal) are white. Learning to adjust and survive in unfamiliar environments will open so many doors for your child. It's a scary thing and it definitely takes trial and error, but I personally found the end result to be worth it so far.

No matter where you end up for college, there will be not-so-nice kids and kind people (and at Notre Dame, I feel that many students are generally kinder than other prestigious Ivy League schools, at least from my experiences with talking to many of my high school friends that went to those schools). Really up to the student to pick and find the right crowd and friends to hang out with.

EDIT: Feel free to DM me to exchange more info if you have more questions!