The way I understand it, Oscar (and any foreign born kid in the US on the F1 Visa) is not allowed to have a "job" in the US. Essentially, the visa is for them to get an education, not earn money. But, it appears Tshiebwe's agent found a workaround that has allowed Oscar to make some pretty decent NIL money already. I believe the very first step was for Oscar to get a Porsche:
That said, the workarounds are somewhat complex and does restrict Oscar's earnings to some extent. There are many folks who think he may turn pro so he can convert to a work visa and not have to worry about silly rules and regulations that pretend he is a normal college student any longer.
-Jason "as for Shaedon Sharpe, he'd have to be a lunatic not to turn pro... he can make mid-lottery money without every risking playing against college-level players... why would he put that in jeopardy by actually suiting up in a college game?!?!" Evans