Short answer: No (not to the best of my knowledge). At many (if not all) universities in Victoria, the deadline has already passed for existing students to add new subjects for instance (you would have already missed so many lectures and assessments it'd severely disadvantage you to sign on any later). So, even existing students don't really have much in the way of change at this point, for reasons which are made obvious by the above.
I would not make the determination you hate nursing off 3 weeks unless its exceptionally (and i do mean exceptionally) bad and such; a huge mismatch to what you expected it to be. You take 24 subjects at university in a standard degree. You are there for 72 weeks in a normal 3 year degree. For this reason, i think it is a bit premature to decide you dislike nursing after sampling 3 weeks out of 4 of the subjects you'll ever take. The subjects next semester might be a totally different experience for instance. That said, the determination whether it really is just that bad or how convinced you are is up to you and you alone so i wont cast doubt on it.
You can transfer mid-semester another degree (almost certainly have to apply via VTAC if it is at a different uni, unless things have changed). Not all degrees accept mid-semester entry. At this stage they will only consider your ATAR score. If you are transfering within the same university, the process is a little easy and more streamlined. Either way, i'd prepare right now so you don't miss any deadlines as serenaaa points out.