i've been playing nb again for awhile, and this team has brought to me quite a bit of sucess. however, i think it can be still be improved though.
Regice @ Leftovers ** Icewhat
Trait: Clear Body
EVs: 252 HP / 96 Def / 140 SAtk / 20 Spd
Bold Nature (+Def, -Atk)
~ Ice Beam
~ Thunderbolt
~...