The top-seeded Canadian team, representing Burlington, Ont., finished the competition with 214.73 points after performing to Gershwin's Rhapsody in Blue. Finland took silver with 214.06 points while Russia scored 203.48 points to win bronze in front of 7,600 fans at FirstOntario Centre.
"I don't think it has sunk in that we are world champions," said skater Lee Chandler. "It was just a surreal experience with the crowd. In the end they really lifted us. This is a program we have been practicing since September and the girls came together today and performed it better than ever."
Finland won the free skate portion but couldn't catch up to Nexxice, who entered Saturday in top spot after winning the short program on Friday.
Skating for Nexxice were Chandler, Shannon Aikman-Jones, Maria Albanese, Ellicia Beaudoin, Emma Bonafiglia, Kelly Britten, Courtney Broadhurst, Alessia Chiovitti, Carla Coveart, Samantha Defino, Courtney Gray, Yu Hanamoto, Renata Khuzina, Victoria Kwan, Kristen Loritz, Nichole Manahan, Kerrin Caitlin McKinnon, Victoria Smith, Kiersten Tietz and Gillian Tyler.
It is Canada's first world crown since 2009, when Nexxice also took gold.
The second Canadian entry, Les Supremes from St-Leonard, Que., produced the fourth best free program to climb from seventh to sixth overall.
Skating for Les Supremes were Elodie Marie Acheron, Audrey Bedard, Jessica Bernardo, Lou-Ann Bezeau-Tremblay, Joannie Brazeau, Sara Irma Corona, Alexandra Del Vecchio, Laurie Desilets, Jacqueline Hampshire, Maria-Victoria Langon, Clemence Lea Marduel, Agathe Sigrid Merlier, An-Kim Nguyen, Minh-Thu Tina Nguyen, Anne-Louise Normand, Genevieve Rougeau, Marina Rousseau, Laurra Olivia Sena, Claudia Sforzin and Yasuko Uchida.
"It was incredible, the crowd showed us so much love," said Desilets. "We didn't feel any added pressure being in Canada. We were really pleased with both our programs and we achieved our goals for this season."
This was the third time Canada has hosted the event in its 16-year history. Canada has now reached the podium in 11 of those 16 years.