1. Stop reading fearmongering media, it isn't good for your mental health. China doesn't have the capacity to even attempt to invade America, they physically wouldn't be able to support any troops in the US, even assuming that they could land troops there in the first place. The US has military bases on every continent including one practically neighbouring China, while China is boxed in by islands and chokepoints. Even if they reached military parity with the US (which is unlikely), geography alone advantages the US immensely in a direct confrontation, to the point where it would be utterly irrational for China to even try. At most they'd go for Taiwan within our lifetimes, anything else is too unlikely to bother even considering for people like us.

2. Even if all of what I said is wrong and China does just nuke everyone out of the blue, there's nothing you or I can do about it so just chill.

Why the hell would you think China would get away with nuking everyone else?