[2] He won a silver medal in skeet shooting at the 2003 European Championships in Brno, Czech Republic, and eventually finished seventh at the 2004 Summer Olympics, competing for the Danish team.

[1] Nielsen trains under longtime coach Kjild Fristrup as a member of the shooting team at SK København.

[3] Nielsen qualified for the Danish team in the men's skeet at the 2004 Summer Olympics in Athens.

He had eclipsed a minimum qualifying score of 124 to strike a silver-medal finish and to grab one of the Olympic quota places available at the European Championships less than a year earlier.

[4][5] Clearly one of the top favorites vying for an Olympic medal, Nielsen nailed 122 targets out of a possible 125 to force a third-place tie with four other shooters in the qualifying round, but fell abruptly in a tight duel to neighboring Norway's Harald Jensen 2 to 1, who coveted the last seed for the six-man Olympic final, relegating him to seventh.