Which is better opt IIT Delhi maths and computing or CSE at NIT Warangal, NIT Surathkal or IIIT Bangalore CSE?

Without any second thoughts, IIT Delhi MnC is the best option among all the aforementioned colleges. It's one of the top 5 IIts and moreover, its MnC program is highly sought after by engineering aspirants. The preference order in your case should be

1. IIT Delhi MnC
2. NITK CSE
3. NITW CSE
4. IIIT B CSE

It's safe to say that none of the above colleges can match the standard of IIT Delhi, which is in itself a brand. MnC is quite similar to CSE though a few core computer courses are not included. Also, this branch is handled by the Mathematics department and not the CSE department. However, if you are more inclined towards CSE than MnC, then the best options for you would be IITR or IITG CSE.