They've wanted to for decades, and now is their best opportunity to invade and take Taiwan. They see the US as weak in general and now on it's knees. Xi is in trouble internally and needs a war to hold power; he has little to lose and much to gain. He'll use the pandemic as a springboard, blaming the US for starting it.
I wouldn't bet on it. About 10 years ago I had it on some authority that Taiwan had three nuclear weapons. That did not surprise me. After all, the South African government had built nukes when they still had Apartheid, we later learned. And both India and Pakistan had developed them in secret until each one detonated six tests.
China could easily conquer Taiwan. All it would cost them would be Beijing, Canton, and Shanghai. Worth the price?
