Decent hotels outside of Nashville's downtown area?

how far from Nashville you want to be? about 20 miles due south on 65, has Berry Farms

Maybe a little closer, but that isn't a problematic distance. What about Brentwood?

Drury plaza in Brentwood

Check out the Homewood Suites by Hilton Nashville-Downtown. It’s a few blocks easy walk or cheap Uber from all the Broadway action, pretty affordable, decent area right across from the federal court, and had a darned good hot breakfast buffet included when we stayed there a couple of years ago. It may be just as cheap as one farther out, and you won’t have to worry about driving/parking if you want to do downtown tourist stuff.