I got my nose pierce when I was 22. That was about 10 years ago. My family and friends always knew it was coming, cuz I always talked about how I wanted one, from the time I was 18 :p My parents never, ever addressed it with me because it never came up when I was younger.
I am a very devout Catholic-Christian and all of my best friends are evangelical non-denominational Christians and they don't care :p They just think it's funny cuz I look all sweet and innocent, but the piercings make you think I'm not. I think the stigma attached to piercings is very much disappearing, tho, as they become more and more common, even among "alternative" Christians, or "relevant" (I hate that term) Christians.
In my place of work 10 years ago, they told me I'd have to take it out for work and put it back on afterward (I worked at a Motherhood Maternity retail store in the mall). They said it would also be acceptable to wear one of those transparent, plastic nose studs that they've created for just these situations. It just depends on where you work, I imagine. If you're a public face, they'll prolly ask you not to wear it during work, but if you're in a casual, cubicle setting, I can't see why they'd frown on it.