Which is the best university among Christ University and Shaheed Sukhdev of Business Studies as per the fee structure?

Yes, you are eligible, as the  NIOS is World wide recognised board.

You must have given cuet UG 25 and got the good marks in cuet ug  25 for Shaheed Sukhdev college or other good colleges 

Through NIOS you can get admission anywhere.

Thank you

Yes, SSCBS not only provides, but mandates a structured summer internship for students as part of the curriculum.

If you're at SSCBS, plan to apply via the CDC portal at the start of your even semester, secure an offer from a firm of your choice, complete the minimum duration, and submit your report

No, for courses like BBA and BMS at Shaheed Sukhdev College of Business Studies (SSCBS), Mathematics is a compulsory subject in Class 12, according to Get My University . So, without Mathematics, Humanities students cannot take direct admission to these courses .

For the BBA (FIA) programme at Shaheed Sukhdev College of Business Studies, both Mathematics (Core Maths) and Applied Mathematics are considered important for CUET UG, as candidates must appear in CUET with a language from List A, Mathematics/Applied Mathematics, and Section III (General Test). 

No, Maths is not important or have any relevance in BBA. but if you've economics subject previously, it will be easy for you to pursue the degree.