Nvidia is buying their own chips and counting it as a sale. In exchange they’re maybe getting OpenAI stock that will be worth more in the future. Normally this would count as illegally cooking the books I think but if the OpenAI investment pays off no one will care.
Still unlikely they’d get prosecuted because they’re not trying to hide how they’re doing this and there’s no reasonable expectation that OpenAI is likely to fold. I doubt they’d improperly record this in their accounting ledger either.