the nose plays a role in the respiratory system as a passageway for oxygen intake.
it also plays a role in the immune system, due to the mucus, snot and boogers that accumulate, protecting the body from infection via the nasal cavity.
it also helps with the nervous system, as it takes in smells and sends a signal to the brain telling you what that smell is.
The nose also plays a role in hearing. The nasopharynx is flanked on either side by eustachian tubes. These tubes connect the nasopharynx to the middle ear. The nasopharynx fills the middle ear with air, equalizing air pressure in the ear with the atmosphere around it, which is an important part of hearing properly, though, that is robably not what you are needing to know.
