Justine Dupont, big favorite of the event after her victory in the previous edition last December, was forced to retire after injuring her foot at the end of her wave.
The Frenchwoman was transported to the hospital for examinations and to determine if it was a fracture or a sprain.
On waves of about 15 meters, Chianca ensured throughout the day to win the title of best performance in front of the Australian Jamie Mitchell and the British Andrew Cotton.
Gabeira, who holds the women's world record for the biggest wave ever surfed with 22.4m on February 11, 2020 also in Nazaré, won in the women's category.
The competition, which is played in Tow-in (the surfer is launched on the wave by a jet-ski) began Thursday morning in a heavy fog which sometimes played the spoilsports.
The 18 surfers invited by the WSL were divided into nine teams of two, forming three groups.
Each group took part in two sessions.
At each session, the two surfers alternated, one surfed the other piloted the jet-ski.
Each surfer's two best waves were taken into account to assign an individual final score.
Nazaré has become in the space of twenty years the most popular spot for big wave surfers, along with that of Jaws in Hawaii.
Water monsters surge at an incredible pace from October to March, thanks to a fault five kilometers deep.
The absolute record recorded and approved by the authorities is that established by the Brazilian Rodrigo Koxa, i.e. 24.4 m on November 8, 2017.
The WSL organizes big wave surfing competitions, with changing formats.
In 2022, there will be three events, the first was played on Thursday in Nazaré, the second will take place again in Nazaré (between November and March 2023) and the third in Hawaii (between November and March 2023).
© 2022 AFP