"has not yet received approval by various antitrust agencies in the U.S., U.K, E.U, China, Japan, and South Korea. Meanwhile, it is widely believed that no regulators or Arm clients want Nvidia to take over an independent designer of CPUs and GPUs, as it will dramatically increase Nvidia's influence on hundreds of companies and even on international projects, such as development of exascale supercomputers in Europe."
Besides Japan, I am not sure if any of the other countries mentioned above will approve this merger. While Nvidia is from US, so are other bigger tech giants in US that will oppose this deal. I feel it will be a no go from China due to fear of US sanction, and also from South Korea since Samsung is also a big user of ARM technology. Each country will look to protect their own technology "Crown Jewels".