Don’t know why, but I was half-expecting You to open Chika’s present at the end and discover that it was something outrageous, like a thong or something (I have a dirty mind). A lovely Christmas doujin either way
Bit of a tangent, but I feel like Nana is one of those characters that could play any stage role: hero, villain, damsel (maybe), lead, supporting role, etc. There’s a sort of versatility to her