I think that if it's something you really want to do and want to take a gamble then go for it, however, please do your research, it is a gamble, the fees for international students are high. During term time, your visa allows you only to work 20 hours were week and you need to consider if that will be sufficient to pay the bills. I'm not sure if your children when they start school, will also be subject to international fees? It used to be that nursing was regarded as something that would always be on the lists, I notice e.g. that on the new WA sponsorship list that nursing was restricted (meaning there are fewer visa's on offer). Graduate nursing positions (after qualification) are also not guaranteed and the situation Blossom described in 2011 hasn't really got any better for places.
Good luck with what you decide.