Snow Tyre Chains are rarely used even though required to carry - the roads from Jindabyne are very good and very easy to drive.  Coming from the other side is another story.  Fly in the Canberra and pick up a hire car at the airport - Europcar have served me well, and they have some of the best customer service at Canberra I have ever come across!!  The drive from Canberra to Thredbo can be broken up (especially at night) with an overnight stop at the modest Marlborough Motor Inn in Cooma, then an early start should see you having breakfast in Jindabyne and on the snow by 10am.