Start the gank out with pinging then when your laner realizes your ready to gank jump on them with your e and w the laner for extra move speed and ult if you have to and there pretty much done

If you are using the tankier build flash into a group of enemys and use randi's and then ult then chase of people that are almost dead your team should do the rest of the work and dont forget to w your adc
If you are using the more damaging build try to bait them into a bush where your ulting and boom teamfight dont use your e on ppl that almost died and w your adc and chase them untill you die thats what the ohmwreaker is for to turret dive them

You start blue with your q and a little leash you should kill it in a few seconds smite it first then when its low use your q and move on to wolves
By this time your should have or about to have your e use your e every time it gets off cool down it will help you clear quick and with your q you will clear even faster after wolves go to wraiths
you will have your e by now and use it once the big wraith hits you once and it should be a quick clear then go to red buff
red buff should be really easy you will smite it early and use your q at the end and he should be done pretty quick then look for a gank bot or top or get golems
Golems kill the small one first with your q and proceed on to the big one and done
Gank bot or top or mid whatever one is pushed the most gank if they are all pushed in get golems
easy as pie

This is my simple guide on how to jungle Nunu for those guys that dont want to have to read that big long guide over there and it teaches you the basics on what to do with nunu he is also a good support if you want to support him try another guide but this one is for JUNGLE NUNU OWNAGE!!
-LoveeYouToo