As AP Nidalee, Your spears are pretty much the most terrifying skillshot in the game if they hit at max range. They WILL reduce non-tanks by 50% or more of their health all on their own. Keep in mind though that as long as you aren't using them at point-blank, you can hit someone with them at a closer range for less damage but an easier shot. If you're harassing, a huge damage hit will probably send people either out of lane or into defensive posture if they survive. While not a gank, forcing someone out of the lane is still good since you get free farm and they lose gold and exp.
You can skimp on wards a little bit with bushwhack, but it's a bad idea against high-speed junglers or junglers who have really good initiation because bushwacks give you less reaction time than wards.
Something to remember is that you can throw down all of your human or cougar abilities, swap to your other form, and use all of them immediately, which is fantastic for chasing since you can pop out of cougar form and throw a spear if they're getting away.
If you're in bot with adc as support, your heal actually does a lot for them in lane fights, because while it isn't much of a heal, it gives them a substantial autoattack buff. You can lay bushwhacks in the side bushes to prevent the other team from lurking in them, and your spears can grab a kill or do a lot of damage in situations other supports couldn't, and if you pop into the river you can throw a spear through the wall if they're tower hugging for a slightly tougher but more unexpected angle.
A big thing; a lot of damage is obvious from the spear skillshot, but you need to use cougar form as well, because it has good burst and decent initation. On low-hp targets, you will do a lot of damage with cougar's Q just off your natural AD as well.
As for AD Nid... well I don't play her that way, because I've played against a few AD Nids as an AP Nid and wiped the floor with them.