Sign him up. He seems happy here, and he's a hell of an outfielder. He's also cheaper than comparable players.
If I were GM, I'd also be seriously considering offering Nick a two year deal, too. Yeah, I know his durability issues, but I believe he's an all-star caliber 1st baseman if healthy. We have to take chances on players like Guillen and Johnson, who are good enough to take us to the promised land, but cheap enough to afford.