After I wrote that comment, I realized that the only way of distinguishing that from the physical world hypothesis is by the prior. Because "there is a physical chair which is responsible for some of my experiences when I am in my room and continues to exist even at the times when I'm not experiencing it" predicts entirely the same things as "God has an idea of a chair in my room, and He causes experiences according to that idea."

So if one is more probable than the other, it would be according to the prior. On the other hand, someone might argue that "there is a physical world that is defined by a certain mathematical theory" and "God exists and has a mental model of a world defined by that same mathematical theory, and produces experiences according to that mental model" may not even be distinct hypotheses. In other words, what exactly does it mean to say that God exists and has a mental mathematical model? And what exactly does it mean to say that a physical world exists according to a mathematical model? Someone might assert that insofar as these predict entirely the same experiences, they are not even different theories, but just different ways of describing the same thing. According to this, Berkeley's theory would not imply that the chair in my room does not really exist, but rather that "there is a chair in my room" means exactly the same thing as "God's mental model includes a chair in my room". So it would still be true to say the chair exists and so on.

Not sure how one would refute that. But assuming they are two different theories, it sure seems like the physical world theory should have a higher prior.