Both are awesome. I think fight between the two can go down with Worf winning or with Chewy winning. Id rather not pick sides giving I'm a fan of both franchises. I think they would make a kick ass team though. But I would urge Chewy to be careful not to cheat in a game of cards with Worf. XD
Chewbacca seems more fluent with technology. But Worf seems more calm and collected in the field of battle. I'd say their battle would all come down to the environment they fight in. If they're surrounded by technology, I'd side with Chewbacca in the long run. But if the setting for the battlefield is out in nature, I think Worf could possibly use the battlefield better.
He was an expert in the Klingon martial art of mok'bara, which he started teaching to other crewmen on the Enterprise, in addition to being proficient in the Klingon bat'leth and mek'leth, and won a bat'leth tournament on Forcas III which saw competitors from throughout the Klingon Empire. He's also slain two warriors in honorable combat, Duras and Gowron, who were both at their times considered to be the most prominent warriors in the Empire. These are in addition to his Starfleet training which has made him proficient in the hand phaser and phaser rifle, as well as his tactical expertise in starship combat.
Chewbacca is no slouch himself, however, with the great strength of the Wookiee species - demonstrated by his ripping a droid's arms out of its sockets - and has experience wielding the bowcaster and the Wookiee ryyk blade. He possesses exceptional skills in piloting and repair and is a master of dejarik, an ancient and challenging hologame requiring skill and strategy.
I get the stuff with Worf's background, but what I've read is that he wasn't portrayed as badass until DS9, with I'm getting that some signs of that is what had him kick some Borg ass in First Contact.