The 20-year-old Walsh showcased why coach Kevin Walters was so keen to bring him back to the club, having a hand in three tries in the space of 10 minutes either side of halftime.
He sealed the deal for the home side with a 76th-minute try to cap a magic Friday night.
"If that's his first game it's great for everyone involved," Walters said of Walsh.
"It was a great start for him. He has good skills in his kitbag but it's only early for Reece.
"We brought him back to do some of the things he did. I'm very proud."
The addition of Walsh has made the Broncos a premiership threat.
His scintillating speed, in combination with the electric No.6 Ezra Mam, was too much for the Cowboys to handle at Suncorp Stadium in front of 43,162 supporters.
North Queensland will wait nervously for the match review committee findings with centre Peta Hiku on report for a crusher tackle on Walsh, winger Kyle Feldt for high contact on Walsh and fullback Scott Drinkwater for a high shot on Oates when he was denied a try just after halftime.
Oates left the field clutching his jaw, Drinkwater was sin-binned and Walsh broke a 10-all deadlock with an instinctive left-foot kick for Kotoni Staggs in the 44th minute.
Walters said Oates was "off to hospital" and was far from happy with the incident.
Cowboys coach Todd Payten said there was no malice in Drinkwater's tackle.
"Scott's tackle happened really quick," Payten said.
"Corey changed direction late. He had one foot on the deck and no intent to make the collision where he got him.
"It was an accident. The kid was doing his best to stop the try."
Walsh blitzed the Cowboys again five minutes later, Mam finishing it for his second try - and the hosts never looked back.
Brisbane were defensively gallant with Walsh and Mam both impressing on that front.
Their attack was next level. Walsh terrorised North Queensland's right edge and Mam, who scored a double, took a mile when given an inch.
The Cowboys set up a thrilling finish when second-rower Jeremiah Nanai chased a Chad Townsend kick, but Walsh had the final say.
Six matches in a row between the two clubs from 2015-2017 were decided by six points or less, including the 2015 grand final won 17-16 by North Queensland.
The match had a similar feel about it from the get-go but it was the Broncos who had the X-factor in attack to make the difference.
The sides were locked at 10-all at the break after both experienced halfbacks shone. Brisbane skipper Adam Reynolds had grubbered for Kurt Capewell to score after Cowboys co-captain Townsend sent rampaging Nanai over.
Walsh got outside the visitors' right edge defence and then a superb in-field kick by Oates got Mam over in the 39th minute. It was a portent of what was to come.
Broncos prop Martin Taupau was also put on report for a hip-drop tackle on Jamayne Taunoa-Brown.
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