Chess grandmaster Daniel Naroditsky died from accidental poisoning after ingesting a drug cocktail that included methamphetamine ... according to authorities.

The North Carolina Office of the Chief Medical Examiner tells TMZ ... Naroditsky had a combination of methamphetamine and amphetamine in his system, along with mitragynine, a substance known for its opioid-like effects.

Last October, Naroditsky was found dead in Charlotte, NC. The Charlotte Chess Center, where he worked, announced his passing at the time.

Naroditsky was revered in the chess world, beginning his career at a young age. In 2007, he became world champion in the Boys Under 12 division at the World Youth Chess Championship.

He also earned the title of grandmaster when he was just 17, and he later graduated from Stanford University before committing to chess full-time.

In addition, Naroditsky taught students at the Charlotte Chess Center and built a large following on YouTube and Twitch, where he provided analysis on high-level chess matches.

Furthermore, Naroditsky served as a commentator for Chess.com and wrote a chess column for The New York Times.

Naroditsky was 29.

RIP