The Canadian country singer MacKenzie Porter grew up on a cattle and bison ranch near Medicine Hat, Alberta. When her brother Kalan won “Canadian Idol” in 2004, she learned a lot about the good and bad of the music industry. She’s just released a new album, “Nobody’s Born with a Broken Heart,” which explores her struggle to make it in Nashville. MacKenzie sits down with Tom in studio to talk about the record and some of the hard-won lessons she learned in the Music City.