When dressing for a nursing interview you want to portray an image of someone who is competent, educated and confident. This is not a time to appear overly casual or sloppy.
Research the medical facility or individual you are interviewing with and try to dress in accordance with the norms of the organisation. For example, you might dress differently for an interview with a popular paediatrician who is notoriously casual than you would for an interview to be a personal nurse for an ailing, reclusive billionaire. Know what you are getting yourself into and dress accordingly.
Although you may prefer to express your personal style in everyday life, an interview for a nursing position is not the time to demonstrate your quirkiness or other nonconformist traits. This is not to say that you can't take reasonable steps to add your own personal flair to whatever you choose to wear for the interview, but try to tone down anything that may be considered immature or bizarre. Nursing is a position in which you must portray the image of a trusted professional at all times.
Take out any piercings that are beyond your ear lobes and try to dress to cover any tattoos. This doesn't mean that piercings and tattoos are wrong, but instead implies that it is better for the interviewer to notice you and your qualifications as opposed to being distracted by your body art throughout the whole interview. Do you want the interviewer to remember your dazzling personality or the skull tattoo on your forearm?
This is not the time for dress-up. If you have no practical experience as a nurse then don't waltz into the interview with a stethoscope around your neck. Consider this as you would any other interview; you want to appear professional and competent. Dress professionally. Wear a pantsuit or professional dress, especially if your interview is at a private practice where you might be more scrutinised than if the interview were with a huge, busy hospital.
Don't wear anything that has stains or tears on it. If you can afford to buy a new outfit then do so, and don't forget to pay particular attention to your shoes and any accessories. Nothing ruins a fantastic outfit quicker than a pair of scuffed old shoes or an absurdly cheap-looking necklace. Remember that nurses are supposed to be neat and clean at all times while working, so you want to convey this to the interviewer even though you aren't working for the organisation yet. If you appear sloppy or dirty then you're not demonstrating the image of an ideal nurse.
Beyond anything you wear to the interview, wear a confident smile and good posture. Nursing can be a stressful occupation, so it's important to demonstrate to the interviewer that you can handle the stress of an interview with poise.
Don't even think about dressing sexy for a nursing interview.
Some folks purchase new outfits for an interview with the intention of returning the outfit afterward. If this is your plan, make sure you don't allow the price tags to show during the interview!