even with shadowball chances are you can toxic stall him out (10% chance of spd drop right?) and tyranitar's only useful as a revenge killer. you can't switch him in anyway so the 2hko is irrelevant
Actually, you might be able to stall out Shadow Ball: 44.41% - 52.30%
That's Timid Chandy's Shadow Ball to Calm 252 HP/252 Sp.Def Sableye.
Flamethrower though: 52.30% - 61.51%
Also, how is Sableye taking an overheat nicely? 76.97% - 90.79%
You can survive, but that's not nice at all.
Oh, and here's a nice scenario with T-tar.
One of your mons die and you send out T-tar to kill the sweeper.
The sweeper gets killed and they send out Chandy and then use HP Fighting against your Tyranitar: 55.45% - 65.35%
That's Max HP T-tar. So Chandy can actually kill a weakened T-tar without much trouble since the only Pursuiter(Assuming they don't have another one, which is unlikely they do) and is free to keep on raping things.