The Waratahs blitzed the Drua early, scoring four unanswered tries in the first 28 minutes - including two to outside centre Georgina Friedrichs - to lead 28-3 and set the tone for Saturday's match.
Miller scored one of those tries in the early blitz with a bustling run down the wing, and she completed her double in the 66th minute to kill off the Drua's comeback attempt.
It wasn't just on the try sheet where Miller starred, with the winger converting all six of the Waratahs' penalties to add the icing on the cake.
The Drua were dominant at scrum time, and denied the Waratahs a winning bonus point in the 78th minute when they stole a line-out and Josivini Naihamu found a gap to score the visitors' fourth try.
Nevertheless, the win marked an excellent start to the title defence for the six-time champions NSW, who started the season without Wallaroos flyer Maya Stewart (ankle), Waiaria Ellis (knee), Faliki Pohiva (concussion) and Tia Hinds (calf).
That was on top of Arabella McKenzie, Katrina Barker and Tatum Bird all departing at the end of last season.
"I'm really proud of the girls. I think we did a really good job to start fast," Waratahs captain Emily Chancellor told Stan.
"We know that Drua are a team that you can't give an inch to. I'm proud of the way we controlled momentum and controlled field position."
The Drua got the margin back to 11 points after a powerful scrum allowed them to score after the half-time siren.
"We talked about it at the end of the first half - we gave them a sniff," Chancellor said.
"They had that mental win from the scrum time on our try line, and we knew they were going to capitalise on that and we were the ones that had to play smarter there."
