I'd read in the past that Nicole Scherzinger had some classical training under her belt but didn't get to see and her that part of her voice until now. I mean, c'mon, "Don't Cha" doesn't really give the girl a chance to show off her voice!

I saw some clips of her Maureen from "Rent" at The Hollywood Bowl and she was quite good there too. I'm truly impressed that Nicole was able to navigate the vocalise section of the song and sing the high E/E6.
These crossover things can be so interesting. Nicole's worked but lots of others fail: check out the Pavarotti and Friends clips on YouTube, for instance. Pavarotti and Sheryl Crow sang "La ci darem la mano" and it was a friggin' HOT MESS all around. Ditto on Sting and Angela Gheorghiu's version of the same duet. Similarly, not all classical/opera singers can sing other musical styles easily. Tatiana Troyanos's Anita in the Leonard Bernstein conducted recording of "West Side Story" comes to my mind immediately. It's so bizarre to hear a mezzo-soprano singing Anita. It sounded so off to me.
But back on topic, good for Nicole!