I did something similar but I did 2 of those clear 1 x 8 bags....1 had the hot chocolate (2 tsp, which is a serving, fit inside 1 of them) and the other had a few mini chocolate chips and 10 mini marshmallows. I made a backing out of cardstock and christmas DSP and it folded down over the top of the 2 smaller tubes and I slide them in a pretzel bag. I cut off a bit and made a topper for it. They turned out really cute! Everyone loved them and I coulda sold more of those but I think I had 22 made and sold them all the first day.
These shown would be way easier! (But I'm not going to lie...I am too OCD to have it like that...the cocoa getting all over the marshmallows would make me crazy! Hence why I did the 2 separate bags. =)
You can kind of see the one left in this pic....back, middle, in a clear holder. The tag is folded back unfortunately, but its a snowman that says something about warm cocoa wishes (its a digital one I bought).