It claims Kaku has developed a theory using "primitive semi-radius tachyons" to prove that we live in a "Matrix".
The source of the claim is this news article from Catholic Online where, surprisingly, the author failed to cite any tenable source to the claims made by Michio Kaku as per the news article. Not to mention that the article is spurious. What Kaku meant/referred to in the Big Think video linked above in the OP as well as one of the comments, refers to the equation in this video. An explanation can be found at this link from Quora.
I think what Kaku meant by the "Matrix" and simulation argument (provided he did say and/or meant so), can be traced back to the 2016 Isaac Asimov Memorial Debate held at American Museum of Natural History where Neil deGrasse Tyson was the moderator. It featured many distinguished physicists, for example, Lisa Randall and Max Tegmark. A report on the same can be found at this article from Scientific American. Many physicists do not believe in the simulation argument, for example; Sabine Hossenfelder and Luboš Motl.
Edit: Here are few more sources of the same claim that Michio Kaku has a proof that God exists:
- Christian Today -- (Author of this article explicitly stated that; "The final solution resolution could be that God is a mathematician," Kaku said in a YouTube video. "The mind of God, we believe, is cosmic music, the music of strings resonating through 11-dimensional hyperspace.")
- Christian Headlines -- (Links back to the article from Geophilosophical Association of Anthropological and Cultural Studies)
Here are links to some articles and statements which debunks the claim of "Proof of God":
- Article from Jay L. Wile's Blog who earned his Ph.D. in Nuclear Chemistry from the University of Rochester.
- A statement from a notable criticizer of String Theory, Peter Woit, regarding "primitive semi-radius tachyons". He is a Senior Lecturer in the Mathematics department at Columbia University and also the author of the blog. The article linked in his comment links back to the same thoughts and URLs expressed in my answer regarding the simulation argument.