This is a pretty easy to play song, although you'll need to know a few seventh chords.
The chords in this song are simple. The thing to remember is the song is in 3/4 time... strum three times per bar (all downstrokes).
Although the chords in this song are simple, they do move at a somewhat brisk pace, and the timing is a little tricky. If you're just getting started, I'd try some of the other carols first.
If you can play an F major chord, you shouldn't have much trouble with "Frosty the Snowman". If you're finding things difficult, you can have a look at the "Frosty the Snowman" performance tips
There are a few tricky chord changes in this one (including diminished chords), so if you're looking for very basic songs to play, you might want to leave "I Saw Mommy Kissing Santa Claus" for now.
"Jingle Bells" is another fairly simple winter song to play. The lyrics and chords can be downloaded freely here, along with some Jingle Bells performance tips
If you're comfortable playing an F major chord, you shouldn't have a ton of trouble with this Christmas carol. To keep things simple, you can just strum each chord four times.
Rudolph is a very simple Christmas carol, with just a few chords. Most guitarists won't have a problem with this one.
Lots of versions of this song are available, including chords for the traditional and "Springsteen version", as well as guitar tab
for a more advanced version of the song.
This is a nice easy Christmas song to play... just a few chords and a simple strum will get you through "Up on the Housetop".