Craft Brewed on Franklin Pike. Great folks with a good tap list. Also has a high gravity side next door (only makes sense to those who know the state regs we deal with.) Ask for Chip, Sean, Jessica, and Ryan.
12th South Taproom has good beer, knowledgeable staff, and good food. Parking is scarce and it can be crowded.
I was only familiar with the Texas locations,but Flying Saucer exists in Nashville http://www.yelp.com/biz/flying-saucer-nashville-3