Consume allows Nunu to stay in a lane against ranged opponents.
You can choose to interrupt Absolute Zero early for partial damage if an opponent is about to run out of range.
It's often beneficial to delay the casting of Absolute Zero until the initial round of disables are used. Try to hang back before rushing into a team fight.
Nunu's Blood Boil allows its target to run away from fights. Make sure to snare and stun any target with Blood Boil on.
Interrupting the charge up on Absolute Zero will lower the amount of damage your team takes.
Using Summoner Flash is a surefire way to escape Absolute Zero.
With only 1 single target ability that can break a spell shield, Banshee's Veil is extremely effective against Nunu.