Career
Nielsen began his career in 1966 at Hjørring before moving to KB in 1970. In 1971, he signed for Switzerland"s Winterthur and he played there until 1973, when he returned to Hjørring. He went back to Switzerland in 1977, with Basel.
Then, in 1978 Lucerne signed him and he retired in 1981.
His last match for the national team was in a 6-1 defeat to Romania on 23 August 1975 in Bucharest.