A rather grim, blow by blow account of the Fort Seybert affair is given in Morton's History of Pendleton County, pp. 42-51. Writing in 1910, he said that only four persons who died were remembered by name, although an estimated 17-21 people were killed. These were Capt. Jacob Seybert (probably actually Seibert), Roger Dyer, a "bound boy" named Wallace, and Hannah Hinkle. Nicholas is a hero of the story as told by Morton.
From other sources, which I could dig up if you need them, I have that Nicholas married Anna Elizabeth Seibert. She was the daughter of Christopher (Stoffel) Seibert and Johanna. Using various sources I have constructed a fairly rich tentative lineage for Stoffel going back four additional generations to 1530. I have no hint of Johanna's lineage.