You may be eligible to get 190 or 489 visa if you are an enrolled nurse in NSW. But, for being a registered nurse you must have atleast a score of 7 each in IELTS or equivalent in other exams. on the other hand you can also start pursuing your bachelors of nursing studies. Please note that you can not apply for 485 after studying diploma of nursing as Enrolled nurses has been removed from the list of MLTSSL.
Hope this helps you. You can always contact our education and migration experts on (02) 9152 8585. We are always there to help you.