Decent set, though I ran some calcs and...yeah, it doesn't take Terrakion's moves THAT well. If SR is up, you're not gonna be switching into a CB Terrakion Stone Edge (or X-Scissor, but XS only ups the damage by a small percentage). It will 2HKO without SR (taking SR into account as it will negate Leftovers). Then of course there's the evil of SubSD Terrakion which no Poke can really handle well.Slowbro@Leftovers
Bold
Regenerator
252 HP/120 SpA/136 Def
-Calm Mind
-Slack Off
-Surf/Fire Blast
-Psyshock
Or the same thing but with CM replaced with Toxic, Fire Blast, Surf, etc. Tons of options.
Regenerator and great defense really makes it a great wall/tank. It also has the ability to take Terrakion's moves, which not many walls have the merit of saying. Not to mention, it has access to Fire Blast, making Nattorei think twice before he switches in unlike other bulky waters.
Now, if you can consistently keep those evil pointed stones off the field, then Terrakion will be crying (other than that SubSD set of course). Or of course, you could just switch into a Choiced CC for free.