Would you class him as the Chess GOAT?
It's not even close.
The chess players to typically be considered for the GOAT debate are Paul Morphy, Capablanca, Fischer, Kasparov, Karpov and Carlsen.
Some of them have easy cases to shoot down. Karpov and Kasparov were at their peaks in more or less the same era, and Kasparov dominated (their overall head to head in terms of games is actually very close, but Kasparov won their most important matches), reached a higher ranking, held the title for longer, etc... which automatically rules out Karpov since he wasn't even the best in his era.
Paul Morphy was insanely talented but he was ahead of his time, playing mostly against amateurs and players who weren't on his level in the 1800's. In fact he was playing before there was ever a chess world championship.
With Carlsen, it's simple: it's still way too soon, although he has the potential to be.
Capablanca is a fascinating case, as his talent is up there with anyone, but he withdrew from chess early and died young. Not to mention, after he lost his world championship to Alekhine which was a huge upset, a rematch could never be arranged (the general consensus even today is that Capablanca would have easily recaptured as his head to head with Alekhine was astounding) and Capablanca continued to be the best in the world even without the title.
And of course, you have Fischer. In terms of talent and contribution, he has a serious case. He's a true pioneer in that he really laid the blueprint as far as opening preparation, physical preparation (he was the first to really emphasize the importance in being in peak physical shape for high level chess, especially leading up to his world championship match with Spasky), and was a true innovator. Probably the most influential player of all time. It says a lot when you're kind of a garbage human being yet everyone is in awe of you. If he hung around, I think the GOAT debate would have been infinitely more interesting, and would have come down to him or Kasparov (for most that's the case now anyway), but I don't see how he can be considered the GOAT when he left the game early. We ultimately go by accomplishments.