There won't be nukes over a very peripheral and essentially civilian uninhabited area.As much as the strategic advantage exists for seizing the Ryukyus I don't think it is a good idea (despite myself having argued in favor of it in a couple other posts- also against it in other posts).
The US can let Taiwan fall and back out, Taiwan is basically in the same state as Ukraine pre-2022. Invading Okinawa is like Russia invading the Baltics, or the Warsaw Pact invading Denmark. That is going to trigger nuclear use from the United States (assuming any US attempt to take back the Ryukyus fails).
As much as the US likes to talk about a years long war, they don't have the industrial base to do that, nor do they have the theory and cohesion to do so. Especially if say, a war starts in the year prior to a US presidential election, the US president will face self-pressure and pressure from his political party to not be the one who lost a war.
Real, traditional, thoroughly institutionally ingrained US strategic culture and thinking is about using tactical nuclear weapons once your conventional forces are destroyed. Not this "do the Long March back to Pearl Harbor and then try and fight a years long naval insurgency along China's SLOCs" crap that has come out of think tanks in recent years.
If that's the logic, US would never attempt anything with Taiwan either, because invading any part of China bigger than a SCS island = immediate nukes?