Murray was drawn in the same quarter as Roger Federer - meaning the pair could face each other in the last eight.
The 29-year-old Scot is chasing a fourth Grand Slam title and his first in Melbourne, where he has reached the final five times.
British world number 10 Johanna Konta, 25, will face Kirsten Flipkens from Belgium.
Konta's draw places her in the same quarter as Slovakia's Dominika Cibulkova and American six-time champion Serena Williams.
Nadal, seeded ninth, will play German Florian Mayer, before a possible quarter-final against Canadian Milos Raonic.