Quote from EricEnfermero
This is going to vary a little bit by state and facility, but NNP's typically perform a lot of invasive procedures that staff nurses typically do not - lumbar punctures, umbilical line placement, PICC insertion, and others. They also prescribe drugs and issue orders.
While they do collaborate with neonatologists and have indirect MD oversight, they aren't usually running off to the physician to double-check every little thing. Where I work, each baby is being cared for by either an MD or NNP, but not both. The MD's remain available for questions, but the NNP retains control of the patient care decisions.
A charge nurse is usually an experienced staff nurse who makes work assignments and can help the other nurses when things get crazy, but they really don't have a unique scope of practice like an NNP would.
Same deal by us. Upon admission, our babies are assigned to the NNP team or the resident team, and both are overseen by the neonatalogists. They have two sets of rounds going on each day - one with the residents and one with the NNPs. Since the residents are "green" still, and the NNPs are not MDs, they do run a lot of stuff by the neonatalogists first but it is their responsibility to examine each patient, then present them on rounds with their plan of care (changes in feeds, meds, ventilation, etc.). Usually everybody agrees and is on the same page.
To the original poster - to be an NNP, you really need to work as a staff nurse in a NICU for at least two years before you can start the NNP clinicals. When you are looking for a job, you want to make sure to find a NICU that employs NNPs so you can observe them on a daily basis. This will answer most of your questions.
I actually thought about becoming an NNP when I was in college getting my BSN. Then I started working as a NICU RN and decided I didn't want that kind of job. I didn't want that kind of power and responsibility, plus I wanted to be at the bedside caring for just a couple of infants each day, not overseeing half the unit!
Only after working in a NICU will you really have a good idea of who does what and which job is the best fit for you. Good luck!