The Oklahoma country-rock phenom Zach Bryan, one of the biggest music-business success stories of the past few years, will spend much of this year on his Quittin Time tour. At various dates on that tour, Bryan’s shows will include openers like Sheryl Crow and Jason Isbell. Some of those nights, he’s playing football stadiums. Last night, the tour began with the first night of a three-night stand at Chicago’s United Center. In the middle of his set, Bryan brought out Kacey Musgraves, and they performed their massive duet “I Remember Everything” together for the first time.