The age of Nidd has been discussed at great length by S.Lévi 1925, who arrives at a date in the 2nd century AD, arguing from the geographical horizon of the text. This date has been disputed recently by Norman 1983: 84,86, who argues in favour of a much earlier date at the time of Aśoka. The question needs reexamination. It is, however, certain that Nidd does not belong to the old canonical texts and that also a date after Aśoka does not seem likely.
In a related footnote (n. 204), Hinüber writes:
But "cannot be later than the date of the fixing of the canon", Norman:Sn-trsl II, p. XXVI: This means not later than the 1st century BC.