The world number one, who has suffered with injury problems in recent years, won the Melbourne Grand Slam in 2009.
"I had very emotional moments this year," BBC Sport quotes the Spaniard as saying. "It's the Grand Slam that I really had more problems with in my career.
"A lot of years I didn't have a chance to play in this tournament that I really love so much with the perfect conditions, so it's very special have the chance to be in the final here again."
Nadal will win his 14th Grand Slam title if he emerges triumphant at the Rod Laver Arena.