In the 1840 Marshal Twp., Calhoun Co., MI there are two Kinyons listed: N. S. and the slightly older William. Perhaps they are brothers or cousins. William stayed there in Convis Twp., as seen in the 1870 census, age 54, b. Canada of foreign-born parents. I think this William has an ID = 121123, using the ID-system of the 1935 "Am. Kenyons", by H. N. Kenyon. I think William had an older brother, ID = 121122, Simon Zolotes Kenyon, b. 1813 in Lacolle, Can. Perhaps Nathaniel was a brother of William and Simon. I would suggest investigating the genealogies of these two, hoping to find some reference to Nathaniel. I wouldn't be too concerned whether Nathaniel was born in NY or Canada, as both are given for William in different censuses. Nathaniel was born during the turbulent times of the War of 1812, perhaps on the border between the two countries. Nathaniel may have returned to NY because his parents (or wife's family) lived there.