Hey there.

Regarding NIT-Agartala, as it was a complete state level engineering college which transformed into national institute of technology  in 2006, it did get accreditations from NBA ( National Board of Accreditation). But these accreditation were given to civil and electrical engineering branches only, in 2013. Regarding the MBA programme that you asked there are no verified accreditation mentioned by the university on their official site. Hope this helps.