Disclaimer: This translation does not guarantee complete accuracy, please confirm with the original page text.
This excerpt clearly shows that there is no connection between the Acharaanga and the Nisiitha. The 57 studies of the Samavayanga have established the 57 studies of the Praacharaanga, Sutra-krtaanga, and Staanaanga. Nisiitha is not included there either.
The Acharaanga-niyukti first gives us information about the connection between the Acharaanga and the Nisiitha. By creating a joint appointment of the Acharaanga and the five Chulaas, a relationship has been established between the Praacharaanga and the Nisiitha. The Niyaktkaara has established the Nisiitha as the fifth Chulaa of the Acharaanga, proving that both the Praacharaanga and the Nisiitha are Angas.
In short, the summary is that the Nisiitha was established as the fifth Chulaa of the Praacharaanga after the Nandi-sutra and before the creation of the Niyukti.
Pandit Dalasukh Bhai Malvaniya has elaborated on this question in his book 'Nisiitha: A Study' and has presented the view that 'Nisiitha' would have been part of the Acharaanga at some point. But there was a time when the Nisiitha was separated from the available Acharaanga-sutra. It should also be remembered that the Nisiitha was the last Chulaa of the Acharaanga, not the original. It is possible that it was added to the Praacharaanga as a Chulaa at some point and, due to special circumstances, the Nisiitha, which was not originally part of the Praacharaanga, remained an appendix. The Nisiitha was included in the Cheda Anga-baahya. Including the Nisiitha in the Anga-baahya did not diminish its importance. Here too, it must be remembered that only the Shvetambara tradition considers the Nisiitha-sutra to be part of the Praacharaanga, not the Digambara tradition. From the Digambara tradition's perspective, the Nisiitha is an Anga-baahya Agama text.2 The Digambara tradition has considered fourteen texts to be Anga-baahya. Of these, six are studies of the Aavashyak-sutra. This also makes it clear how ancient the Nisiitha Agama is. It is self-evident that the Nisiitha-sutra existed before the division of the Shvetambara and Digambara traditions. The following verse appears in the Acharaanga-niyukti:
Navabambachearamaio attaraaspayasahaassiyo veo.
Havai ya sapanchchulo bahu-bahutaro payaggen. ||3 This verse makes it clear that earlier there were only nine Brahmacharya studies in the first Skandha of the Acharaanga. After that, it increased and became the first Bahu and then Bahutara. Based on the Acharaanga, the first four Chulaas were created and these Chulaas were added to the Acharaanga. The introduction of the Acharaanga in both the Samavayanga and the Nandi Agamas mentions twenty-five studies, but the Nisiitha is not included with it. When the Nisiitha was added to the Acharaanga, it became Bahutara from Bahu. The Nisiitha was added to the Acharaanga between the time of the creation of the Agama-soochi mentioned in the Nandi and the time of the creation of the Acharaanga-niyukti.
1. Havai sapanchchulo. - Acharaanga-niyukti 11 2. (a) Shatkhandagaam Bhaag 1 p. 96. (b) Kashayap-ahun Bhaag 1, p. 25121
Acharaanga-niyukti verse 11
24