I just caught the end of it, so I'm not really sure what this cartoon was called, but the main charater was South Pole Joe.  

It was really a pretty lame excuse for a cartoon.  Joe dressed in black and carried a black sack and delivered really lame gifts on April 15th, then got made when he wasn't a popular as Santa . . . Then Santa (doing his taxes at the last minute) got the feeling something was wrong and took off to where South Pole Joe was causing his problems . . . the fought, then made friends, then realized that they had held everyone up and everyone's taxes were going to be late, so Santa finished filling out forms while South Pole Joe collected them and got them stuffed into the mailbox just before midnight.

The cartoon's only saving grace was that South Pole Joe was driving a White over Black 23 Window Ragtop Deluxe Mircrobus.  That's the only reason I even stopped on Nick when I was scanning through the channels.