Hello student!

Yes, mathematics is a basic requirement in almost all colleges for the MCA program.

I will suggest taking the Board Examination for only mathematics through NIOS. This way you'll be able to add mathematics to your mark sheet. You do not need to appear every subject all obver again, appear only maths as an additional subject. This is because you already have a 12th mark sheet, and after appearing NIOS boards for maths, the marks will add to your mark sheet.

You can go through the article to get a list of colleges providing MCA program and other details too:-

https://www.google.com/amp/s/it.careers360.com/articles/top-mca-colleges-in-india/amp

All the best!