Nunez, who has made just two substitute appearances for Leeds since joining at the end of August, has spent most of his career in America with FC Dallas and Chivas USA and last played for Honduran side Olympia before arriving in England.
He was a second-half substitute in Leeds' 4-0 home defeat to Cardiff in October and played the last seven minutes in the 4-1 win at Scunthorpe in the same month.
Source: PA