Try Cowpie (click here), Hummingbird. You'll also find songs Nanci Griffith wrote listed under Kathy Mattea and maybe Suzy Bogguss. You may also find other sources of chords at the Mudcat links page. Another place to check is OLGA, the on-line guitar archive. You can also search Yahoo and find lots of stuff about Nanci. Not much stuff about her here, though.
One thing that might help - she spells her name Nanci Griffith.
-Joe Offer-