China is rapidly expanding its nuclear arsenal and could have more than 1000 warheads by 2030, according to a Pentagon assessment published on Wednesday. That's a faster buildup that U.S. officials forecast a year ago, suggesting Beijing could overtake American power by the middle of the century. It comes a day after President Joe Biden said he did not want a war with China over Taiwan. The U.S. has promised to help the self-governed island defend itself against Chinese claims. But it follows a series of dire warnings from U.S. officials that China is racing to overtake U.S. military might…