Personally I feel Nidalee is very unforgiving and carries the weight of the win or loss on her shoulders significantly more than many other champions. The combination of her skill and niche way to impact the mid-late game needed to utilize her without being a wet noodle that dies in a stun is difficult to execute correctly, but extremely potent when played right.

If you don't have strong game knowledge, aren't an experienced jungler with good map awareness, or don't understand what a team comp can do to you when you commit to a leapQ, even if you have her core mechanics down, avoid her at all costs. She's not the champion to learn these aspects of the game on in the slightest. Believe me, I tried a very long time ago.

Nidalee is complicated at first, especially regarding her clear, switching skill sets (needing to know the feel for cooldowns you can't see) and most of all landing her skill shot is what defines her. She has to land a skillshot, towerdive, or dive onto a backline target near other enemies and escape with low defenses for a lot of her kills in a lot of her games. A strong Nidalee will carry the game, make the enemy tilt and probably force a few afks and surrender at 20 the most often of any jungler I can think of.

On the flipside, a bad-mediocre Nidalee that hasn't gotten fed, after the 20m mark will kind of just land every 4th spear for a small chunk of damage on the frontline, then probably die in a single CC after she leap Qs someone after she tries to pick someone from the backline or both teams commit to a fight. You're essentially looking at a mobile ward that does 400 damage every 30 seconds in this case and you'll probably lose for it.