There are many sources for Giganotosaurus videos. There are the typical tributes that people make all over Youtube with sometimes awful music (in my opinion of course). There are also original source videos such as this episode of Chased by Dinosaurs, a BBC show which would later spawn a slight spinoff of the idea of time travel called Prehistoric Park. The episode which we are interested in is Land of Giants in the Chased by Dinosaurs series. Here I started with a clip from the show, other links to the other parts follow. For some odd reason Netflix skips this episode but has the other two.
Another place, though not in a documentary standpoint, that Giganotosaurus appears is the show that replaced Prehistoric Park in its time slot, Primeval. A series of highlights from that episode of the show, which takes place at an airport, is put together below.
Dinosaur George answered some questions about Giganotosaurus on a number of different videos. I have only included one, but going to his page and searching the uploads you can find over 20 more.