I never understood this about Nazz...
...In most episodes she tends to act friendly towards The Eds - Allows them at her parties, gives them snacks, and, usually with Double D, does some favors for them. She also, in a blue moon, come to their defense.
But in OTHER episodes she partakes in making fun of them, like in Your Ed Here and All Eds Are Off, like she really wants to see them fail and fall lower in the social circle in the Cul-De-Sac. Usually, this is when she's around Kevin and it's been suggested throughout the series, especially in Big Picture Show, that she has a crush on him, but some of the nice stuff she's done for The Eds have been when he's around so what's with that?
I know The Eds did a lot of bad stuff to the kids in The neighborhood and what not but even so she seemed to cool off pretty quickly, much moreso than the other kids did.