Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Nunu is an interesting champion that can easily be made into a tank. This build show how to make nunu into an almost unkillable champion that can easily support his team and get some kills to.
Very high heath and mana with good heath and mana regen
Very high armor and magic resist in unison with Force of Nature, Banshee's Veil, and Guardian Angel will make this nunu nearly impossible to kill
good movement speed
Zero armor penatration
slow attack speed