Bay Area all-star group the Nell & Jim Band are a fresh new iteration of veteran grassers. They dip between folk, swing, jazz, and blues, finding a common thread in music that is joyful and well-crafted. Nunally may be familiar as a member of the David Grisman Bluegrass Experience, and you may know Robinson from her Joe Henry-produced 2014 record “Rose of No-Man’s Land,” which was adapted for a PBS special. Alongside three other West Coast pickers — Jim Kerwin (upright bass), Jon Arkin (percussion), and Rob Reich (accordion) —  they form a wonderful ruckus.