I would never place Nidalee in tier 1 or higher. Those tiers are basically the "These champions are broken here because they're balanced in SR" tiers. Compare the strength and utility of other mages there, Evelynn, Brand, Zyra, and arguably Amumu, and Nidalee does not come close on either the "broken by mechanics" front or the "broken by SR numbers being used" front. Tier 2, on the other hand...
I won't lie in that she's a great solo queue champion like Akali, Elise, Kayle, Talon, and Fizz, or anyone with unexpected upfront burst and a way to escape 1v1's, but AP Nidalee will typically not win a close range fight when forced to it, whereas the comparisons here have a good chance of it. That is the sacrifice her kit made when it took jungle control as a strength. Granted, she won't willingly fight a straight up fight very often since she can kite so much, but being forced away from the typical jungle camp locations is turning her into a speedy Ezreal -- essentially taking her out of her jungle->lane harass role for the duration of the zoning which is probably what the enemy team needs at that time (for capping points usually).
Against organized teams, Nidalee's effectiveness will fall quite a bit. She excels at harass and escape and in pure solo queue games she has the capacity for litterboxing on people due to lack of collapse movements in the jungle, but in organized team games she will fall in effectiveness quite a bit -- down to that of a regular burst mage -- because she has to be in expected places to fire those spears. If there is one thing Nidalee cannot handle well, it is people collapsing on her from 2 directions instead of 1. Keeping Windmill neutral until a second enemy comes from their jungle? No problem, easy flee. Did they come from your side of the jungle? Welp you're screwed unless it's Garen or someone with minimal CC.
The thing is, she's built around kiting so she will always have a very positive KDA ratio, and much like Leblanc and other bursters with escapes this can make them seem better when their weaknesses aren't being showcased because nobody on the enemy team is shutting their strategy down. There's a lot of situations with Nidalee that one can use for argument examples, and she wins most of them -- however Nidalee is a jungle poker so most of these are 1v1's, skirmishes, or other position-heavy situations. I could make a big list of them, or I could go just write a TL;DR and go to sleep since it's 3am on December 25 and just respond later, and other people could give their thoughts on Nidalee too.
I guess what I'm trying to say is that I consider Nidalee balanced/strong and I already had half a mind to move AP Nidalee up a bit simply based on what I've seen lately (and because of the reduced number of Hexdrinkers in this meta, it's funny to see people die to her traps), but also that she would never be tier 1 in her current state or on her current numbers. Tier 1 is basically the "If Dominion was League's primary game mode, most of these champions would have been hotfixed" tier. I just can't justify her being on the same level of those guys.
TL;DR I consider Nidalee a balanced champion on the strong side, but she can sometimes seem way better because she's heavily skewed towards particular strategies and fares abnormally poorly with other strategies, on top of high KDA ratios because kiting is her game. I was already considering moving her up to the front of tier 3 or end of tier 2, but she just isn't broken or exploitable like the champions in tier 1. A case could be made for moving further up in tier 2 though. Okay time for sleep.