So, does he have regen or not? And its a lot harder to not get hit by a nano cloud than you make it out to be. He can't hold his breath because they'll just crawl into his body anyway, and it only takes a little bit to have enough explosives to give him an aneurism. Regen makes that void, but meh. He'd have to dodge the grenade and make sure he isn't anywhere near the gas explosion. Either that or we just call batman. And if he has no regen powers, whats stopping someone from internal hemorrhaging him?

Gotta give him at least Cell levels of regen for him to not be a pushover to anyone who can cause internal damage.