Linda Chorney, a Grammy-nominated singer-songwriter who grew up in Sudbury, will soon be returning to her home state to screen “The Opening Act,’’ a documentary that she directed and stars in. The film, centering on the question of what defines success for musicians (including Chorney), will have its New England premiere as the opener of the Newburyport Documentary Film Festival on Sept. 16. After the screening, Chorney — whose album “Emotional Jukebox’’ was a best Americana album nominee at the 2012 Grammy Awards — will perform. She will also answer questions accompanied by her first manager, local jazz impresario Fred Taylor, the music director and concert promoter at Scullers Jazz Club.