If they lose their minds and drop the big nukes, your $1,000 worth of rice and 9mm ammo won't mean much. If you can't breath the air and everyone has radiation sickness, then you are a goner either way.
But if it continues to be simmering/serious regional "stress" around the world and small wars among proxies (like in Yemen or Taiwan), then you won't need to buy sandbags for your house in Ohio. The Yemeni aren't coming to take your truck, you'll be fine.
An attack by one major nation on another would destabilize everyone's economy, fuel supply, food supply, etc. There is no global player who wants that. Somebody like ISIS might want that, but they are 5,000 angry guys living in Western Iraq, so they don't really call the shots.
p.s. Pepe, how would you get to Southern Argentina in the case of a global shutdown?