"What are some creative, not too nerdy professions that nonetheless require a talent for math, engineering, or science?"
You are implicitly assuming here that your niece WANTS to make use of these things in her profession, which is a pretty bad thing to assume. Why don't you ask her what she wants?
I've experienced this constantly in my life. Relatives of all sorts tell me "You should become a doctor" or "You should become a radiologist" or whatever else. I turn around and say back to them, "Hmm, sounds like if you think radiology is so wonderful, maybe you should go back to school and become a radiologist."
It is, IMO, really rude to just start suggesting things to people. ASK what they like and what they want to do. If they don't know, there is no reason they even need to know yet.
Ask your niece what she is interested in and support her in her choice, or if she doesn't know what she wants to do, help her lead a life where it's ok not to know yet. Don't be a dick and try to force/coerce her into math or science just because she is good at it and you want her to do it. Being good at something doesn't automatically dictate that you will enjoy a career in that field.