Sydney Airport is truly appalling, if you want to are forced to go there, and transfer from the domestic terminal to the international on the other side of the aerodrome.
The OP could fly from BNE to LAX directly and save several hours, so must have a good reason for going via Sydney, but if you want to go to Santiago you are forced to go via Sydney, and Qantas assures you that it's no trouble at all - but it is, so it's clear that an hour would be difficult. Qantas ground staff act as though time has stood still. Ho hum.
The domestic leg was subject to NSW's daylight saving, and we had 1 hour 20 minutes, and of course the aircraft was half an hour late, so it was panic stations. We made it, just, after worrying all morning and spending a few hundred dollars extra on an airport hotel just so we could make the only QF flight from Sydney to Santiago.
My daughter and her husband weren't so lucky, a week ago; QF BNE-SYD then LATAM SYD-SCL an hour twenty or so later. This time it wasn't the domestic flight running late, it was the Qantas ground staff failing to transfer their luggage from domestic to international. Yes, they got to the international terminal in time only to find that their luggage which had been checked all the way through to Lima wasn't even there.
I only go to Sydney when I am forced to do so, such as to get to South America. Its airport is truly dreadful.