Is it correct to say "He is a one in a million type of person and student", for instance? To praise someone, meaning he is one of a kind. What expression would you suggest if it is not? I want to use this phrase in a sort of nomination but I do not know if it even exists, thanks a lot!
Yes, this is something native speakers say. It's not an especially common expression, but I don't see anything wrong with it. You can find some examples if you search online. When I did, I found this quote by the comedian A. Whitney Brown:
There are a billion people in China. It's not easy to be an individual in a crowd of more than a billion people. Think of it. More than a billion people. That means even if you're a one-in-a-million type of guy, there are still a thousand guys exactly like you.
To me the phrase sounds somewhat informal.
In my opinion, a proper way to say this is ...
He's a great person/student. He's one in a million.
Here, the idiom one in a million means -nearly unique; one of a very few. Note that you can also say one in a hundred but beware, that person might feel this as praising quite less ;)
[Example from TheFreeDictionary.com]