There are many university which offer MCA programme. Each university has its own criteria to take the admission. Some of the university takes the admission through its own entrance exam & some of the universities take the admission on the basis of merit list.

If you want to get admission in NITs then you need to appear for NIMCET entrance exam. As per the eligibility You must be holding graduation degree BCA/B.Sc (Hons.)/B.Sc/ BIT as per 10+2+3 pattern from a recognised University. You must have studied Mathematics or Statistics or equivalent subject during graduation degree to apply for the exam. You an check the complete information about NIMCET with given below link.

NIMCET

Good Luck!