– 16th century) was a Danish colonist and acting governor of Tranquebar from 1643 to 1648, in times when overhoved Willem Leyel was absent.

During his service as acting governor of Tranquebar, Nielsen would defend the town from Thanjavurian General Tiagepule and support a mutiny against overhoved Leyel.

[3] However, Nielsen did not care much for Pessart's drunkenness and was therefore appointed as merchant on the Gilded Sun by Claus Rytter[4] on a voyage to Makassar in 1642.

[8] In another letter to Leyel, dated 20 December 1644, Nielsen describes how an Indian general from Thanjavur had appeared outside Tranquebar with a large army, demanding that the inhabitants give him 600 rigsdaler as a present.

[10] With gifts to the value of 3.000 rigsdaler and heavy negotiation, Nielsen managed to persuade the Nayak to give compensation for the general's attack.