Basically. It's all about timing. It's not like he can create an impassable defense of mortar and grenades. It might seem that way but trust me, it's not.
If the snake player hasn't mastered grenade stripping, catch them when he throws em and send em back at him(you'll have to be kinda close to get this to work). You can air dodge mortar when it's coming down and fair him. After he's in the air, don't give him a chance to recover. He'll probably nade some more, but he can't nade cook while he's in the air, so just be sure to throw em right back. After you get in, it's all about keeping the pressure on. That's the best way to handle campers =]
If you want, you can glidetoss it into him with a reverse/forward glidetoss, and then immediately Counter. Note the glidetoss sends you like 2/3s of FD's length so if you have to stay close to him to even grab the grenades, I'd prefer a glidetoss AWAY from him (roll backwards, cancel into forward toss, you'll travel backwards all the way back to the other side probably). From here, you can repeat the same thing until he stops spamming the grenades. Although this takes some tech practice, but it's basically like Samus' super-wavedash in Melee IIRC distance-wise, but slightly nerfed.
From then, you can apply pressure and force Snake to be on the move. If Snake gets aggressive, be cautious and be
extra aware of your spacing. Counter if necessary. In this match-up, I'm generally going with Ftilt over Dtilt. However, if you can predict that he's going to throw move X (Ftilt for example), Dtilt and use the IASA frames to activate Counter. The Dtilt then acts as a low-lag bait for you to get in damage until the Snake takes notice (take note of the range of Ftilt though, you can't Counter if you're dead >_>).
You'll be playing mostly on the ground here, so if Snake screws up and/or leaves himself open, Dancing Blade is generally the way to go. If you're close to the edge, do downwards ending stabs, or neutral slash to set up for edgeguarding.
The ending sword strikes ("Sword Dance") send him in a lower trajectory, which will force him to eat up damage by making him use C2 to get himself back on if he can't just with Up-B alone, or force him to recover near the edge if he hasn't mastered C2 tech-to-stage at higher percents. From the latter point, grabbing him out of the Up-B kills him (make sure you don't jab him or the hit recovers his Up-B). Play it safe and edgehog to make sure nothing funny happens after you grab release.
At lower percents, upward slash as your 4th Dancing Blade sets up for some nice Utilt juggling. Upthrow does similar here if you can get it in. Fthrow and Dthrow can set up for Dancing Blade or Fsmash if you prefer.
Generally, just play it safe. Don't try to be all flashy; stick to what works. But glidetossing is an option if you can't resist. =P Just know it's not at all necessary though.
Oh and yeah, should I have completely screwed up how this match-up usually goes, please do tell me. I never get far enough in tourneys to fight the good Snakes lol (although I only attended 2 tourneys and generally spend my days practicing spacing w/ lv.9 CPUs, only to scream in anguish because they Perfect Shield every ****ing thing I throw at them).
