Funky Glitter Christmas is the best NMIXX song.
Title. It's creative, catchy, and fun. The references to a ton of other christmas songs makes it really fun to listen to. This stage with live vocals in particular really sold it for me.
Not saying their other songs are bad, just saying this one's the best.
I believe this opinion is unpopular because most people's favorite is either DICE or COOL.
If I had to rank them I'd probably do 1. Funky Glitter Christmas 2. DICE 3. COOL (Your Rainbow) 4. O.O