It appears to be a Taylor NS-42CE like the one I just bought used at Guitar Center. (Which is now my favorite guitar in my collection!). PlayinG along with the recent Zac Brown and Jimmy Buffet Crossroads on CMT it alos appears to me that he's got the guitar tuned down one step.
According to AG Magazine article in the 4/2010 issue he plays a Nylon string Taylor NS72ce with Rosewood sides and Cedar top. He flat picks it. He also has a Collings Winfield Sunburst. The tab for "Chicken Fried" is in the mag. It is played utilizing key of G chords but is tuned down 1/2 step according to the article. EADGBE are all flat.
He talks about getting a unique sound flat picking a Nylon string.
I believe he may also use a Godin ACS nylon string also as others have used it as a flat picker, although the article says his electrics are a LP and a custom Strat.