Decide yourself how much pots and wards you need, I start normally with 3 Sightswars plus 3 Health Pots, but this choice depends on your match up (you need more HP-Pots when facing a aggressive lane or you need more wards and Mana-Pots when staying longer in lane, for example when you have an easy matchup).
Considering this start will sometimes cause an instant report from your teammates, but I wanted to show this option. You get the same Manaregeneration, plus some AP and some HP. However, you cannot use the passive of Dorans Ring properly since you should not do lasthits as support. This item can help you to be more dominant in the lane, but you are more vulnerable to early ganks. If you start with Dorans Ring, port immediately back when you have 700 Gold and buy a sightstone.
A good start with any support I tested and appreciated. The 2 Sightwards are not this much, but when they are both gone, you are about to port back anyway and then you can get an very early Sightstone. You get more HP-Regeneration and you get your Philosophers Stone earlier. This start is awesome if you are facing an passive lane.
An important item you should build as fast as you can. It gives some nice gp10 and sustain. This item is a coreitem on nearly all Supporters and Nidalee makes no exception.
The relatively new Sightstone provides free wards. In former times Support was an awkward role, but with Sightstone you can acutalle just sit back with your Sightstone and gp10-Items and relax. Keep this item forever and upgrade it lategame to a Ruby Sightstone.
This item fits to Nidalee since she needs gold and AP. Pretty strait forward, buy it only if you can afford it early and if you have Philosophers Stone already.
If the midgame arrived and you just got the money for Kages, skip Kages and buy Chalice instead. You need the Mana-Regeneration and the Kages is just to late.
This are the boots you want to buy. They grant you MagicPen, which combined with your Masteries, Runes and your Traps make you deal almost truedamage with that Javelin.
I do not like to build these Boots on Nidalee because she already has relatively low cooldowns and she is manahungry so your Mana will be disappearing even faster.
Buy these boots if there is much CC in the enemy team or when they have much AP. I do not recommend these boots because you need the MagicPen, but when you are focussed in teamfights, Mercs are a solid choice.
Rushing these boots makes no sense and you do not need them in the midgame. However, you can build them if they have a team of AutoAttackers.
When you need an Enchantment then it has to be pure Movementspeed. Homeguard could also be an option but I consider pure Movementspeed to be more useful.
You can sell these boots very late lategame to get an defensive Item like Mikaels' or Banshees', but you will barely reach a full itembuild.
In the late lategame with nearly full itembuild you can replace this item with 5 pinkwards everytime you visit the shop.
This items makes you think 'Ouch!' everytime one of your spears hit. The AP got decreased but it is also cheaper now. I would recommend this item if you have won your lane and you need offensive stats to be useful in the teamfights.
Nidalee is manahungry, and this item is the solution for this. If you spam spears you will recognize it though, you need an other item with Mana-Regeneration to really get rid of Mana-Problems. Athenes also provides some AP, CDR and MagicResist, so it is an overall good choice.
Actually not bad, but this is an mid-game item, where you want to rush an expensive item like Rabadons to compensate your supportrole. If you failed your lane and still want to be useful, build this item.
This item is an lategamechoice since you have early- and midgame enough MagicPen. But when the enemy team is stacking MagicResist, this item helps you to deal really harsh damage.
Providing a slow Rylais compensates your lack of CC a little bit. It also gives a ton of AP and HP which help you to get along in teamfights. If you hit a spear with that slow it will be a guaranteed kill because the target is slowed and on half HP.
GA is a great lategamechoice granting lategame survivability. In a long game your death can cause a loose until you respawn, waht is why you should grab it as one of your last items. With Flash, Pounce and GA you can escape a secure death.
This item is new and pretty useful though. If your AD-Carry is fed and you want to save him from (Off-)Tanks attacking him buy this item. The stats are okay, but the active in combination with your heal helps your AD-Carry out of almost every situation.
AP, CDR, Mana-Regeneration, all this are stats that are very useful, but you should build this item only if you are facing a team of healers like Volibear or Mundo, or if they have a really fed ADC. Then you can use your Q or your E to reduce their MagicResist, Armor, Healing (plus slow with Rylais).
I consider this item to be not this useful. First you do not have a CC which impairs their movementspeed and secondly you do have many abilites that do spelldamage.
I do not play this item on Nidalee because it is not useful. There are way better choices to get AP and Mana-Regeneration.
This item is a must-have in your team. With this item opposing MagicResist will be irrelevant, and you get some nice AP and MagicResist from it. The Problem is, when you thros spears at max range, your Abyssal will not decrease the opponents MagicResist because it has an relatively short range. Ask your Midlaner or AP-jungler or AP-Toplaner to build this item, do not build it yourself.
The Aegis is also a musthave in any team, but it will be better build on your jungler or your toplaner. Nowadays nearly everyone wants to build this, so feel free to skip it.
I personally do not think this item fits to Nidalee, you do not need any sustain in teamfights because of your awesome range and pokekit. Also you cannot ensure your team will be in range of the aura. Do not build it, but it is nice to have on other teammembers.
You have enough good AP Items and Lichbane does not scale the full AP anymore, you do not even want to use the passive, because you want to poke from a range which is higher then your AA-range. "This item is so useful on Nidalee" said noone ever.