After bowling out NSW for 170 from 30.4 overs, Queensland was cruising at 4-144 before a flurry of wickets saw the final five overs turn into a tense chase.
Queensland finished 9-171 with just three balls left from their allotted 40 overs.
Sunshine Coast product Zoe Valencic picked up 4-35 from eight overs while Bundaberg's Lucy Hamilton claimed 2-21.
An opening stand of 72 by Taylor Stumer (43) and Lucinda Bourke (29) helped Queensland off to an ideal start in their chase,
Captain Sianna Ginger hit 26 to keep the run-chase ticking along before it hit a pothole, Queensland losing 5-16.
But nerveless batting from Holly Smith (15no) and Darcey Johnson (3no) saw Queensland home.
Queensland was coached by former Irish international Ciara Metcalfe, with the Wynnum-Redlands coach in the Katherine Raymont Shield assisted by QC State Talent Development Manager – Women’s Cricket Mark Sorell for the campaign.
The Queensland Under-15 men's team finished second last week, winning five games and suffering its only loss in the Final when defeated by Victorian Country in the titles in Ballarat.
There were three Queenslanders chosen in the Cricket Australia Under-15 squad include Redlands left-arm spinner James Pullar, Wide Bay allrounder Jack Geldard and Toowoomba pace bowler Joseph Fry.
Valley allrounder and Queensland captain Hugh Weibgen was named player of the championships while Gold Coast wicket-keeper Lachlan Aitken finished with most dismissals, claiming nine catches and seven stumpings.