Hi,

Yes, Nios is a legitimate board that competes with icse and cbse. It is the largest open schooling board in the world. It is a recognised board within the Indian central government's Ministry of Human Resource Development, and its certifications are recognised not just in India, but around the world, in any stream (science/commerce) and at any college (public/private). And to answer your question, yes, all graduate schools and universities in India accept NIOS dual enrollment or half admission students, including IITs, NITs, DU, JU, and IIITs.

Hope that answers your question