Nikolaj Hübbe, artistic director of the Royal Danish Ballet since 2008, knows George Balanchine’s Nutcracker intimately. After all, Hübbe was a principal dancer with the New York City Ballet for 16 years. The Balanchine classic, now a holiday tradition in Copenhagen, was choreographed in 1954, and is lovingly rooted in the original Mariinsky production, which was created in 1892 by Marius Petipa, Lev Ivanov, and Pyotr Ilyich Tchaikovsky. Of The Nutcracker and its power, Balanchine said, “In every person the best, the most important part is that which remains from his childhood.” —L.J.