The only really noticeable thing Chibiusa does in this story (other than exclaim about the snow) is to propose that everyone have a Christmas party. She remembers when she was the Party Star and got Diana as a Christmas present. It is the cutest ever. Oh, and later Chibimoon and Tuxedo Kamen combine forces to preform Pink Sugar Tuxedo Attack. Don't ask me. I have no idea. Chibiusa is also the one to nominate Luna as the Party Star and ask Super Sailor Moon to use the ginzuishou to turn her human for a night.