Nvidia is in early talks to provide up to $250 billion in financing guarantees to help OpenAI lease computing capacity from a planned $500 billion, 10-gigawatt data center facility in Ohio, according to Bloomberg, citing people familiar with the matter. The proposed deal highlights investor concerns that the AI bubble has been fueled by circular financing. The SoftBank-led project is located in southern Ohio and, when fully built, would support 10 gigawatts of computing capacity, or roughly equivalent to the output of 10 large nuclear reactors.…