Both IIIT Allahabad and MNNIT are highly regarded engineering colleges in North India offering premium quality education. Placements-wide, MNNIT CSE is slightly better compared to both NSUT and IIITA. In my opinion, the preference order should be
MNNIT CSE >= IIITA IT > NSUT CS/AI
MNNIT is the first choice because it’s on Eid the top 5 NITs with the most sought-after branch CSE. IIIT Allahabad is also a great choice for CSE because it has a CS-tailored curriculum and ambiance.
Overall I feel if you are certain of joining an IT company, and have an interest in coding and computers go for IIIT Allahabad IT or MNNIT Allahabad. If you are unsure of your branch preference go for NSUT.