I heard an interview with him this morning, where he's already in China. Some of his stated reasons for the move (also listed in the articles below) include the slashed research funding in the USA, increasing restrictions on research and international collaborations, as well as wanting a stronger push for the AI revolution in science.
https://www.kompas.id/artikel/when-nobel-winner-in-chemistry... https://www.yahoo.com/news/science/articles/why-nobel-laurea...