AP Nid is a decent addition to a team, and fun to play. There are a few constraints however.
First of all even though she is ranged she sucks at farming before lvl 6.
Then she isn't really that strong 1vs1, she needs to land a good spear (that will take 1/2 hp of soft targets, 1/3 of bruisers and around 1/4 of tanks) before going in in tiger form that is in turn tricky to control and enemy might take advantage of it.
And probably most important is for her to have a good team to cover for her farming weakness early and to occupy enemy later in teamfights, ad bruisers work the best here.
Played properly she has a huge psychological impact on the enemy team, she makes enemy carries think twice where they are standing and force them to go b at 50% hp to avoid getting one-speared, her traps, although not as damaging as teemos shrooms provide great vision once activated, with Lichbane her tiger form is pure terror and did I mention her 400+ heal?