It depends. We tend to have all the fixtures in the same finish to have the uniformed look while we sometimes purposely mix up different finishes with cabinet hardware, light fixtures etc. If you are only taking about faucets in the same kitchen, I would not mix up chrome and BN. They should be the same finish. If you're talking about something else, such as cabinet hardware and faucets, I often mix up finishes. Hope this helps.

Here's an ideabook on mixing finishes. I mixed chrome pendants with brushed nickel hardware in my kitchen.
http://houzz.com/ideabooks/3222120

It doesn't have to be all matchy matchy

http://www.plumbedelegance.com/it-doesnt-have-to-be-all-matchy-matchy

Thank you everyone for your comment. My husband had a fit when my lighting I picked in the house we are building was chrome but we also have brushed nickel in faucets and knobs. I was very ok with it but I wanted to truly set my self at ease :)
He will just have to accept it, lol! Thanks again to all

I say you should be able to decorate your kitchen and other areas of the house... give him his shop or man-cave. We try to agree on interior/exterior ideas, but when he cooks... he can decide what goes in the kitchen!

I'm not sure my whole link worked or not. I actually have a blog post that talks about this and shows photos of mixing finishes. If you search on "matchy" on our website you'll see it.