Apart from the fact that she's not African American, even though Tessanne Chin has Black heritage, she fully passes for an Asian woman. Like people who didn't already know her wouldn't say she's Black when asked to describe her, which is fine and doesn't invalidate her Black heritage. But seeing as prejudice is exercised virtually all of the time based off of somebody's phenotype, I would not use her as a representative example of a Black winner of the show, as she doesn't go through life exactly the same as how unambiguously Black women do.
It's sad to say but I fully doubt that she would have won the show if she were a dark-skinned, unambiguously Black Jamaican woman. This show and the USA in general need to do better...