AD Nidalee is better with a Solo-Front mega tank so the enemies won't focus on her until the tank dies.
AP Nidalee is more flexible with frontlines.
Guide
When to play:
TLDR: As long as you hit Nidalee 2-stars, it's worth playing!
Both AD and AP Nidalee are VERY flexible with items.
AD Nidalee can do very well with burst damage items such as Infinity Edge, Last Whisper or fighter bruiser items.
AP Nidalee can do very well with not only Guinsoo's Rageblade but also Mana Generation items such as Blue Buff and Spear of Shojin.
However for AD Nidalee, there is a specific condition which will make her S+ tier.
And that is the Hunter Emblem!
Because Nidalee will always target and jump on the lowest health enemy champion, this makes her always able to secure the kill for herself. And Hunter Emblem gives a lot of AD per kill, this makes Nidalee the No.1 best user for Hunter Emblem.
Blue Buff + Silvermere Dawn is another S+ tier combination, this will make Nidalee one-shot everything and gain CC immunity as well.
2 Stars Nidalee + 2 Stars 4-Costs Tank (For AD ihey are normally Malphite or Sett, For AP Nidalee they are Sentinel or Amumu) At Lv8
Strong mid-game tempo, since this is a 8-4 comp.
Itemization
For AD Nidalee
Like we have mentioned, Hunter Emblem is the best item on AD Nidalee.
Then, because she is an adaptor, she has already got a lot of AD from the trait and Hunter Emblem, so you don't have to build too much AD on her. Blue Buff is perfect in this case because it gives 10% of extra AD she already has, also makes her cast faster --- Nidalee will be able to jump between enemies non-stop and carry really hard.
For the 3rd item, both Infinity Edge are Sterak's Cage are very good. You can also do with Hextech Gunblade, Spear of Shojin or Edge of Night.
For AP Nidalee
Guinsoo's Rageblade is very good, and strong on many carries early. Nidalee is a Magic Marksman, and her casting animation speed is tied to her attack speed.
Jeweled Gauntlet + Striker's Flail make the best combination. Since the Adaptor trait already gives Nidalee some AP, being able to crit + the damage amp will make her super strong; sometimes she can even one-shot the backline.
Morgana is a 2nd/support carry, so give her utility items.
Void Staff for the magic penetration, Morellonomicon for Burn/Wound.
Adaptive Helm is the best 3rd item, since it will make Morgana gain an additional 15% mana from all sources, and being a fighter her auto attack already gives her 10 mana, so she doesn't need Shojin + the items we mentioned, she already has a lot of mana regen.
For Your Main Tank (Malphite, Sett, Sentinel, Amumu)
It's much better to solo-front them with Gargoyle Stoneplate.
Warmog's Armor adds health on top of the resistance.
Crownguard is considered the best tank item right now.
Tank BIS: Gargoyle Stoneplate + Warmog's Armor + Crownguard
How to roll/Leveling
Roll at 4-2 or 4-5 after you reach Level 8. Sometimes you can't level to 8 at 4-2 because in this set we have less resource and gold than previous set, so you maybe have to wait two more rounds until after the Carousel.
Don't roll straight to 0. You should keep at least 10 gold so your econ can come back.
Be flexible with your frontline, as we mentioned, almost all 4-costs tanks are very decent right now. Be flexible and adaptive just like Nidalee!
Once you hit 2-stars Nidalee and 2-stars 4-costs tank. you should try to reach Level 9 for the 5-cost support carry such as Ashe, Gnar and Alune.
Opening Examples
Rengar Opening
Rengar opening is the strongest early opening you can get. Try force AD Nidalee or 3-stars Rengar as hard as you can once you hit the Hunter Emblem early.
hunter Emblem is made of Pan + B.F. Sword. The Gold Augment "Cooking Pot" can give you a Pan, then you just need to find a B.F. Sword to complete the key condition.
Azir is super strong early and perfect with AP Nidalee's items. Yorick is super tanky, and Blossom upgrades your wisp for even more advantage. Those upgraded Wisps are super OP right now, you should definitely try it out.
AP Adaptor Blossom Opening
Using Adaptor itself for pivoting is also very smooth, but you have to make sure your main tank is upgraded. Otherwise, once he dies, Master Yi will be exposed to enemy fire. Or you could make Edge of Night on Master Yi, but you will have to reforge that later on.
Advanced Tips
Kog'Mow can provide magic penetration, so you don't have to build Void Staff on Morgana if you are running it.
Play Alune at 9 and transfer items from Morgana to her once Alune is 2-starred.
Rerolling for Nidalee 3-stars at Lv8 is also a great way to secure 1st placement. Since Double Nidalees are pretty strong anyway, this makes it a natural process.
Choose The Bear for Primal's Blessing in order to execute low health enemies.
Hit other AP carries such as Soraka and Zyra on the rolldown but not Nidalee? Don't worry! We have the guide prepared for you! <3