The Boston Pops and Tanglewood Festival Chorus, under the direction of Keith Lockhart, perform “Christmas Canticles”and “Hallelujah Chorus” from Handel’s Messiah; country singer Sara Evans, who performs selections from her 2014 holiday album “At Christmas”; and actor Robert Morse (“Mad Men”), who reads “Twas the Night Before Christmas” with musical accompaniment. From Symphony Hall in Boston.