Alright this guide is built around the fact that your jungling/tanking/ and you want your ultimate to get off normally Mercury Treads are way better then Ninja Tabi but Ninja Tabi come with dodge which can dodge abilties like cryptic gaze to help ensure your ultimate hits people.

I use Glyph of Focus because it helps your jungle and improves your ganks with Iceblast when you can get it off faster.

Seals of Resilence because your tanking and it does help your jungle out so it works both ways.

Mark of Insight should be self explanatory never met a decent Nunu who wasn't using them.

Quintencesses of Fortitude because it helps your have more health to gank once you start and it helps tanking and early jungling.

I use these masteries because im tanking and I wanted to have neutral buff increase for jungling. These are standard tanking Masteries.

The items are built around you ultimate and tanking. Ninja Tabi can dodge abilties like Cryptic gaze which would interupt your ultimate normally. Banshees veil also works like ninja tabi. Radiums Omen use it right before you start your ultimate to ensure they don't escape from it. Rod of Ages its tanky and it makes your ultimate more effective. Sunfire cape for AoE,health,and armor. Warmogs for more health so you don't die. Why is my item build surrouned around my ultime so largely. In a team fight if your ultimate gets off and hits 2-3 people atleast you probably won the team fight and even if it hits noone they want to get out and it can help scatter your enemies.

Most people like to cap one abiltiy first I like to keep the generally even although Iceblast is probably your most important ability. You need to put your first point in consume or you can't jungle. Second point in Blood boil to increase jungle. Third and Fourth point in iceblast for ganking and to speed up jungle since you have blue buff and can spame it although you do run out of mana around double golem if your spamming it but its usually regened by the time your in position to gank.

Smite is because your jungling obviously. I choose flash over ghost because blood boil is about equal to ghost shure they do stack but if blood boil didn't let you escape something probably happened to where ghost wouldn't of either. And flash out of a bush to pull of an easy gank and to escape death.

Pros
. Hes an Awesome jungler
. His ultimate is one of the best in the game if you use it correctly
. Awesome Ganks
Cons
. Not the best tank

Alright when your yeti spawns you should buy a cloth armor and 5 health pots and head to blue camp with your teammates to ensure you don't die you can have someone leash it if you want but its perfectly soloable start off by popping a health pot then wait tell youve lost a bit of healt then consume so it heals you for the max amount (make shure not to use it to late) then smite Golem once its enough to kill it to ensure noone in a bush or stealthed steals it. Once you ding put your second point in Blood boil and just spam it.Next consume big wolf and finish off the little wolves by autoattacking next head off to banshees consume the big banshee and auto attack the rest. Next head to lizards your smite should be up start off by consuming it and popping a health pot btw you should of put your third point in iceblast. Just rinse and repeat tell you can finish it off with smite. Then do double golem and then I recommend you gank a lane since you have 2 points in iceblast and both buffs.