Floreana Giant Tortoise is extinct, the name has a confusing history, also there's some effort to find turtles with Floreana ancestry and reintroduce them https://www.galapagos.org/newsroom/floreana-tortoise-species-resurrection/
But Reptile Database a no longer considers Chelonoidis nigra an active taxon and it now includes Chelonoidis nigra as a synonym of 13 other turtles
https://reptile-database.reptarium.cz/search?search=Chelonoidis+nigra&submit=Search
so I think its safest to swap this into the genus rather than try to map it to some other species