So as an international student you will not be eligible for a commonwealth funded university position - so you will need to pay full fees upfront (Also if you come on a student visa you are not allowed to work more than 40hrs a fortnight)
As you already have a bachelors degree you may be able to do a Masters of Nursing practice which is 2 years full time - The cost at the moment for full fee paying international student is approx $65000 AUD
If you need to do a full bachelor of nursing then as a full fee paying international student it will cost you approx $116 000AUD
As for doing study in the US and then emigrating
1. It is virtually impossible to meet APHRA (the national registration body) standards for a registered nurse with an ADN
2. If you are doing your BSN in the US be very sure that you get an accurate record of your clinical hours & that your university will be happy confirm these hours with APHRA - you must have completed 800 clinical hours in your training to meet APHRA standards (basically this is the biggest difficulty US BSN students have when coming to Australia )
So within Australia, there are officially only two types of nurses
1. Enrolled Nurses - this is a (generally) 18-24 month course conducted via TAFE or a similar training organisation (I think this is similar to like a community college in the US). EN's can further be divided into those who are IV medication competent & those who aren't, but IV medicine competency is increasingly common. ENs are employed over a wide variety of practice areas however are far less common in critical care areas (ED, ICU etc) and are more common in areas such as Long term care and aged care. ENs are also employed by higher numbers in private hospitals compared to public. At the basic bedside level there isn't a massive difference in practice between ENs and RN, however, there isn't the same opportunity for career develop - you can't move into supervising, management etc as an EN. Also RNs are better paid. ( I think an EN is the equivalent of a US LPN)
2. Registered nurses - This is either a 3-3.5yr bachelors degree (or less commonly a 2 yrs Masters degree) at university. RNs work in a large variety of practice areas. They have a greater capacity for career progression and are better paid than ENs.
There are significantly more RNs than ENs in Australia
Australian registration for RNs and ENs is national, not state based, so once you are registered you can work anywhere in Australia
Graduate nursing is a very competitive market - the most common Job that new nurses get is a graduate program/transition to practice program. This is where you get a fixed term contract (generally 12 months, some are 18-24) where you are hired and work as a registered nurse (or EN) but receive additional support as a beginner practitioner HOWEVER these are hard to get, so for example in my state only about 50% of graduates got a graduate position. Once you are registered you can apply for any entry-level nursing position, however, it becomes a lot harder as most employers want experience. This also means that if you decide to do your bachelors in the USA you will want to work for at least 1 year (and preferablly 2) before coming to Australia, or else you are just one more graduate RN without experience looking for work.
You will want to be an Australian Permanent Resident by the time it comes to graduating & looking for work, because if you aren't, you are not eligible to apply for graduate programs & you can't be employed by a public hospital (unless they can prove that there is not Australian citizen or permanent resident available to do the job) ...and public hospitals employ approx 2/3 of nurses in Australia.