nios board student can give AIIMS and NEET

AIIMS and Neet examination depends upon your board marks and not upon the board precisely
you need to score a minimum aggregate in 60% of each of physics, chemistry, biology and English to be able to qualify for AIIMS being and unreserved candidate and 50% in each being a reserved candidate
for Neet the cutoffs for unreserved candidates a 50% of aggregate in each of physics, chemistry and biology and 40% in each if you are a reserved candidate
Hope this helps, thank you