Nicholas Northup, Esq., of North Kingstown, died in his 81st year.
I have made an assumption that both of these marriages are for this particular "Nicholas, son of Nicholas."
Nicholas Northup, Jr., witnessed a North Kingstown will around the year 1766. Nicholas & Hannah Northup witnessed the will of Hannah Allen, dated 12 Dec 1805, North Kingstown. Possibly she was Hannah Northup's mother (?).