Jón Ólafur Jónsson (born 14 July 1981), also known as Nonni Mæju, is an Icelandic basketball player and a former member of the Icelandic men's national basketball team. He was a key player on the Snæfell team that won the Icelandic championship, the Icelandic Basketball Cup, the Icelandic Supercup and the Icelandic Company Cup in 2010. He retired from top-level play after the due to lingering injuries.