At USN, you can either apply to take a full degree, or you can study one or two semesters as an exchange student. Exchange students have to be nominated by their home university before they can apply. Full degree students apply on their own and do not need to be nominated in advance.
Students from countries outside the EU/EEA/EFTA must pay tuition fees, but there are some exemptions, for example for exchange students. You can find all the information about exemptions and fees here.