Nvidia investing up to $100 billion in OpenAI to help build out data centers ... featuring Nvidia chips. This is for a 10 gigawatt project containing between 4-5 million GPU units, which is about the total number of GPUs Nvidia will be able to ship this year.
So Nvidia has $100 billion dollars, buys a stake in OpenAI, who then spends that money buying GPUs from Nvidia. So in essence Nvidia gets a stake in OpenAI in exchange for GPUs.