There are few dwellers, let alone champions, residing in the blasted and dangerous lands that lie south of the Great Barrier. Much of that world still bears the scars of past Rune Wars, especially the mysterious ***ungu Jungle. There are long-forgotten treasures in these strange places which many risk life and limb to acquire. The champion known as Nidalee was only a young girl traveling with her treasure-seeking parents when they lost their way in the dense, rainy jungles. The jungle was unforgiving, and she watched her parents suffer agonizing final days as they fell victim to a mysterious and vicious disease.

As improbable as it was for a child to survive in the inhospitable jungle by herself, she did just that. Her youthful innocence and a fortunate naivete caused her to appeal to the beasts of that place and she was taken in by a family of cougars and raised as one of their own. She grew and somehow absorbed the raw magic of the dense wilds, evolving beyond both her human physiology and her feline affectation. On one pivotal day in her life, standing over the torn remnants of a Noxian squad of woodcutters, Nidalee chose to rejoin the so-called civilized world, to fight in the League of Legends so as to protect the vast woods from both Demacia and Noxus.

Pros
-Best heal in the game
-Can be played as AD, AP,Hybrid or even AP Support
-Very good Map Awareness through Traps
-High damage output
-Strong Sololaner
-Strong Pusher
-High Mobility
-Dominant in Lane

Cons
-SQUISHY!!!
-Likely to be CCed
-Needs skill to play her right especially the junping through wall with W-Spell

In my opinion you should take the runes you need for solo Nida but in my opinion the Marks should always be Magic Pen.
For yellows you can either use Armor(which I personally prefere for some survivability against ganks from the jungle)or Mana Regeneration per Level for people who need to heal themselves often in the laning phase.
For Blues I go Magic Resist but you can also go either CDR or AP.
The Quintessences I take 2 APs and 1 Movementspeed. Why? Well, I take W first to put some traps in order to protct the jungler from ganks and to pull the Golem with 1 trap this is the reason for taking movement speed runes. Ap Runes for a better Heal at Level 1.

I take standard Caster Masteries 9/0/21.

I start with a Doran's Ring for HP, AP and Mana Reg because I dont take Mana Reg Runes in yellow Runes.
My first items are Sheen an Boots of Speed you really need that farm on your lane.
Your first big Item is Lich's Bane for some nice damage with your Spells especially with your Q as the Cougar.
Rabadon's Deathcap for AP.
After Rabadon's I take Voidstaff for more Magic Pen and my last 2 Items are Zonya's Hourglass and Abyssal Scepter for some survivability.

I take W first to guard my jungler.
I don't skill it untill my Q and E are Level 5.
The first Spell to skill is E for Lane survivability.
Q next for some damage in team fights.
Take R whenever you can.

I take Ghost and Flash fo Map control and running :D
Exhaust works well on Nidalee too as well as Ignite and Clarity.

Nidalee has a very unique Heal.
It is the strongest heal in this game.
It can heal up to 1000 and thats the half of the health of most Champions.
Another unique spell is her Ultimate.
Her ultimate gives her 3 new Spells who deal tons of tons of damage.

As a solo laner you really need 99& of the creeps in a wave.
You lasthit only with auto hits but in Mid/Late game you can also kill the Magic creeps With 1 W+E combo as Cougar.