We recommend 3-4 days for a first-time visit to Nashville. This will give you enough time to see the city's most popular attractions, such as the Country Music Hall of Fame and Museum, the Grand Ole Opry, and Broadway. You'll also have time to explore some of the city's other neighborhoods, such as East Nashville and Germantown.
If you have more time, you could also visit some of the day trip destinations near Nashville, such as the Jack Daniel's Distillery or the Civil War battlefields at Shiloh National Military Park.