When you do this move with Lili she pops out a penguin.This penguin can charge your opponent and trip him/her.To do this press down + square + triangle the the penguin will pop out of nowhere.To make it charge press down + square + triangle while crouching
To defeat Nancy, first you need to use your ultimate move(like avenger of Jin Kazama) that at least damages half of your enemies life. You also need to use sidesteps to easily avoid Nancy's attacks. But still if I was you I don't like the bonus of Nancy. The bonus is just a maximum of 50,000 gold. I just love to defeat Nancy that's all.