Could be the classic "while looking at diamonds far away can't see the ruby in front of me" with Nat eventually winning Carl over or something.My guess, Nat is there to help Carl to get the blonde girl on Mat's side to whom he is secretly in love with but as a nerd certainly not on the blonde's radar.
Nat will be the focus at the party and opens somehow a way for Carl to get the attention of his secret love.
Mat of course needs to be consoled...the next mission for Nat!