May 24th, 2017: Added more champions to threats, mainly ones who can stop the channel on your ult.

June 14th, 2017: Added sections on ganking and teamfights. Added Shyvana matchup. Added section of full gameplays and clips to help explain things better.

June 16th, 2017: Added another video to the gameplays/clips section.

July 31st, 2017: Added Top lane Runes, Masteries, Item Set, Ability Order, and Lane Matchups.

August 5th, 2017: Realized I put the masteries in wrong in the original build, like an idiot. Fixed them. Added second set of masteries for when your team is gonna be trash.

Oh boy! It's been a while!
November 8th, 2017: Added Runes Reforged.

January 26th, 2018: Nunu is back baby! Updated for new runes and a new carry style build. Go forth, and eat the jungle once more! Also added synergies section so you know who's AMAZING to have on your team with the Yeti.

May 17th, 2018: This guide is a year old now! Holy cow! My girlfriend and I had a baby, so there was a decent amount of time where I didn't update the guide, but I'm back, and ready to fix what's wrong. New item paths, new skill orders, new items, and new runes. Also added a new gameplay video where I get a 21 KDA. Not too bad.

May 18th, 2018: I forgot to take Tracker's Knife off the build list. It's not even in the game anymore. What am I even doing?

Hello! I usually go by PlunkSenpai, but as of late, I've been going by the name of my new account, BardcoreP0rn. I made a second account to play ranked on, since I was getting too stressed out worrying about my rank on my main, and ended up buying Nunu with IP since he was so cheap. I didn't really expect to play him, but I accidentally picked him one game, and did so well that I just kept playing him every game I got the chance. I currently have a 77% win rate with Nunu Jungle, and I want to share the love and teach others to play him as well.

Both builds use the same runes for a few reasons. I chose Guardian because most of the time you're going to be using Bloodboil on an ally to give both of you the buff, so Guardian is an obvious choice.
With your E, you're going to proc Font of Life constantly, making life easier for your teammates.
You have insanely healthy clears early, so Conditioning gives you the most bang for your buck, giving you extra MR and Armor from 10 minutes on.
Revitalize gives you more healing with your Q. It's good.

The secondary tree is Precision for Triumph, since you're going to be participating in hopefully a lot of kills. Triumph will keep you in the game for a longer period of time.
Precision also gives us Legend: Tenacity. Tenacity is good on Nunu. It lets you get into the middle of the fight and eat up the CC for your team while making it a lot less inconvenient for you. As long as you gank well, you'll get plenty of tenacity.

With the Helping Yeti build, your goal is to keep your entire team alive while soaking up a ton of damage, laying down shields, and providing buffs and healing to your carries. With the new version of Bloodboil giving the target increased AP, this can now extend from just your ADC to your Mid laner. Your job is to run into the middle of the fight, eat all their CC, and pop Absolute zero in their faces while using your item actives to keep yourself and your team going.

With the Carry Yeti build, your goal is to gank really, really hard. You'll want to rush into the lane, bloodboil the laner, (The ADC if you're ganking bot lane.) throw snowballs into the enemy's face, (The ADC if you're ganking bot lane, yet again, unless they have a Janna or Soraka. Then kill them first.) and keep slapping them with your meaty yeti hands until they're dead. Once you've gotten your damage items, get some tank items to keep you from falling off hard in the late game, or go full AP and have your teammates bait your enemies into a bush ult to get a hilarious penta.

Smite: Always take smite if you're jungling. Even with Nunu. A bite and smite combo should secure any objective.
Flash: The best escape tool you've got. Use it.
Ghost: Also viable, but I prefer Flash.
Exhaust: Also viable, but I still prefer Flash. No point wasting an Exhaust to try to escape the enemy jungler coming to fight you because you took their buff. Could help you win the fight though, so maybe.

For the first build, always start Q to clear your jungle and keep you alive. Any other start is wrong. Max this first for better clear and sustain. We don't need a lot of damage to do our job anyways.

Take W level 2 and max it second. It's going to give us the attack speed and damage to finish off our second buff without using smite. We save that for the opponent's second buff.

Take E at level 3 for ganks, and max it last. The extra damage doesn't mean much since we're not going AP, but the extra slow is WONDERFUL for ganking.

Put a point into your Ult at every level possible. It's great for teamfights if no one can cancel your channel, and even if they can, it's still good because everyone is going to be either focusing you or running away to get out of your ult, even though you don't hit that hard with it. It's the fear factor really. Everyone expects Nunu's ult to deal stupid amounts of damage, so they stop fighting and run away instead.

For the Carry build, start Q>W>E>E>Q>R, then max R, E, W, and Q, in that order. This will give you solid clears and good ganking potential early.

Start with Machete, Refillable potion, and warding trinket. This is easily the best start and gives you everything you need to clear the jungle, and you can pretty much stay there indefinitely as long as you abuse your passive.
You can either recall when you get 1100 to get Bami's Cinder, or just keep farming/ganking. I prefer to do the later, and only recall when I absolutely need to or am getting to be less effective. I can usually get Cinderhulk, Ninja Tabi, and either half of Frozen Heart by the time I recall for the first time.
You're going to want to rush to finish your Frozen Heart next, and then build whatever your team needs most. I usually build either Locket or Knight's Vow depending on if my team is ahead or behind. If they're ahead, Knight's Vow will push your team over the edge and you'll easily win fights. If you're behind, Locket gives your whole team an extra chunk of HP that will keep them in the fight longer. Redemption works as well in either case, but I usually prefer to build it last, or if our support isn't going to.
The notes for the alternative items pretty much cover when you should get them.

Situation 1 - Your opponent started bot side:
Start at your bottom side buff, and ask your teammates to leash decently hard and stand guard for invades. If the enemy team has a Blitzcrank, they're most likely going to try to invade.
Take your first buff, and try to finish it off without using your Q more than once or twice. Drop a point into your W, and walk to your second buff. Abuse your passive. Try to get free casts of your Q whenever you can. Pop your W on yourself to clear it even faster. Don't smite unless you have to.
Immediately run over to your opponent's top side buff and take it. Trust me, you should have cleared your buffs fast enough that you can get to theirs before they do. Ward over the wall so you know if they're gonna spoil your party. Once you've finished the buff, or have been forced off of it, run and take Scuttles. If you see the enemy jungler while you're in river, try to follow them, because your top laner has probably pushed their lane way too hard, and they're about to get ganked. By this point you should be level 3, so snowball the absolute **** out of them, bloodboil your laner, and try to kill them. Once you've accomplished this, go take Krugs, Raptors, Wolves, and Gromp. You should be level 5 by now, and can easily solo dragon. Ward it up, keep an eye on your mini-map in case the enemy mid or bot start coming to wreck your day, and once you've taken it, go gank another lane if you have an opportunity. If not, keep farming until you see an opportunity. If you can afford Cinderhulk, you should probably recall and get Tracker's Knife and the red trinket. Start warding up the enemy jungle, and steal their buffs whenever you have a chance. Snowball it from the bush so it comes in after you, then just take it. I've had games where the enemy jungler showed up right after I got their buff into the bush and they didn't even think to check if I was still there because they just expected me to be gone already.

Situation 2 - Your opponent started Top side:
If your opponent started top side, just take your bot side buff, then theirs, then your top side buff. After that, everything is the same. Take Scuttles, keep an eye out for the enemy jungler, ward river for your lanes, and gank and farm as much as you can.

Ganking with Nunu is both super simple, and one of the hardest things to do. You HAVE to get your laner to engage on the target, or they're just going to walk away or use their escapes once you're seen.
There's a __ step process to successfully ganking, and here it is.

Step 1: Make sure your entry point, and all points on the way are not warded. This can be accomplished with red trinket and control wards. ALWAYS HAVE A CONTROL WARD ON YOU.

Step 2: Ensure that the target is pushed far enough that the gank isn't going to be a total bust. If they're back too far, you're not going to accomplish anything. If they're not at least half way down their lane, don't bother.

Step 3: Always ping the target and ping for help. If your laner doesn't get the hint, ping "On my way", and if they still don't get it, tell them in chat to go in.

Step 4: Once your laner has engaged the target, run into the lane and snowball them, immediately followed up with a bloodboil on your laner. This will give both of you the additional movement and attack speed necessary to take your target down.

Step 5: Stay on your target, using your Q on minions every chance you get to keep your health up. Spam your snowball at your target every time it comes off cooldown. You should be able to get 2-4 off on them depending on what rank and how much cdr you have at the time.

Step 6: If they flashed and escaped, you have about four and a half minutes after they get back to lane to try for a kill. If they died without flashing and it's up, try ganking them as soon as they're pushed again to burn their flash. If they flashed and died, you can probably get them again when they come back. As long as their flash is burned and/or they died, the gank was a success. Congratulations!

Bonus step: If your laner is willing to give you a couple of their minions, bloodboil them and take the tower. Make sure you have all possible entry points for their jungler and other laners warded. Keep an eye on the mini-map while you take the tower. If you see someone near you go missing, or your wards spot someone, back off.

As the second support, your job is pretty simple in teamfights. try to make sure no one dies.

Run right up to the enemy team and snowball their carry. Your Frozen Heart will lower everyone's attack speed, so being right in the middle of the fight is almost always the best plan.

Use your ult immediately if they have hard cc. This WILL make them target you with it, and it will save your carries from it during the fight.

Make sure you have Knight's Vow partnered up to whoever is currently the strongest on your team. Try to do this well before the fight so that if they die, you can switch it over to the next strongest.

Use your Locket to shield the team as soon as the fight starts to give your team a huge advantage.

If things are still going south, dump your redemption right into the middle of your team. If you can hit some of the enemy team with it too, that's beautiful.

Snowball the **** out of the biggest threat. Keep your carry bloodboiled. Stand on top of their ADC if you can so they get absolutely plowed by your Cinderhulk. Eat minions to stay alive. If you're fighting in the jungle, chow down on raptors or wolves if possible.

Be as annoying as you can. You are Nunu after all.

Kog'Maw is incredible with Nunu. You give him insane amounts of AS, plus the AP boost when he's built Rageblade helps out a lot. 10/10, would duo with.

You synergize incredibly well with Kayle. You give her AS and AP, and those are the only two things she really wants and needs. 10/10, would duo with.

This bird boi is similar to your synergy level with Kayle. He's super strong with the AP and AS buff from Bloodboil, and his ult can throw the enemy into your ult, or throw them out. Eh... 8/10, would duo with if he knows what he's doing.

Time for a true display of skill? Yes. Absolutely. With his AS stacking passive, and the AP scaling on his W, E, and R, you pair extremely well with this guy. 9/10, would rather have Kog, but he'll do.

Rat boi does love himself some attack speed, but the only AP scaling he's got is a .2 scaling on his E. That being said, your slows can keep the enemy team in range of his ult for a bit longer, and that can mean the difference between winning and losing a teamfight, and/or the game. 5/10, would rather have Ez or Kog.

You have no idea how much porn I saw while getting this picture. Ahri likes to weave auto's between her abilities, and you make that happen better, plus you give her extra AP, which she likes. 6/10, would play a game with.

Instead of continuing, I'll just wrap this up. As long as the champion isn't an AD caster like Riven or Renekton, or someone who barely uses Auto Attacks like Garen, they're going to pair pretty well with Nunu after the buff to his W. If they're AP and the like to have attack speed, they're going to be your best friend forever as long as you keep that bloodboil on them at all times.

This first video is a full game with commentary. This is exactly how your games should go if everything goes well.

Play Video
This second video is another full game with commentary. It's a pretty decent game where I talk about counterjungling, the importance of objectives, and how well things can go when you secure important objectives like Rift Herald and Baron early.
Play Video
Third video with full commentary. It's one of the best games I've ever had, and I ended with a KDA of 21. Not too shabby! Play Video

If you've read this far into the guide, I want to thank you! I've only put out one other guide so far, and it didn't really do that well. Please, feel free to leave any thoughts, comments, and/or criticisms, and I hope you enjoy playing this build as much as I do. :D