NIOS 12th

The students should score at least 45% in their 12th for this course.
12th
Aggregate of one language and three best elective subjects would be considered as best four subjects (BFS). Environmental Education (ISC), Fine Arts, Graphic Design, Painting, Dance, Music, Physical Education, Home Science, Engineering Drawing and all other vocational subjects are not considered as BFS.

Please check for your eligibility to pursue B.E. in Computer Science Engineering at M.V.J. College of Engineering from the criteria mentioned at the link provided below.
https://www.shiksha.com/b-tech/course/b-e-in-computer-science-engineering-m-v-j-college-of-engineering-whitefield-bangalore-153438

Yes, students who completed their 11th and 12th or only 12th from NIOS are eligible to give the entrance exam for IIT Bombay so as to get admission.

Please check for eligibility to pursue B.Tech. in Marine Engineering from The Neotia University at the link provided below. Admission process, fee and course structure are also mentioned at the link provided below:
https://www.shiksha.com/b-tech/course/b-tech-in-marine-engineering-the-neotia-university-diamond-harbour-road-kolkata-249632

Admission is based on the marks obtained in 10+2. Interested candidates can apply online with the required information. Candidate must have passed 10+2 in any group from a recognized board. There is no prescribed age limit for this course. For further details regarding this course, please refer to the link provided below:
https://www.shiksha.com/animation/course/b-sc-in-animation-subbalakshmi-lakshmipathy-college-of-science-madurai-258387

Hello Rahul,
Sorry that I saw your query only today. The online process of accepting applications for UG courses in DU had closed. If you had seen and registered on this portal then I am sure you will shortly find results on the same portal about status of admission.

The candidate from PCB group will, I hope, appear for 10+2 from some other board. NIOS is another board but it is not a requisite for BBA. Admission can be taken in BBA if the candidate has 12th with PCB also. It is not compulsory to appear for NIOS.

I advice you to please go through the official website for eligibility criteria.
http://www.ipu.ac.in/pubinfo/admission2018/adm2018main/ADMBRO2018A_190218.pdf
Follow the brochure.

Every institute has different eligibility criteria for the admissions. I advice you to please go through the official website for eligibility criteria.
Link: http://www.ipu.ac.in/pubinfo/admission2018/adm2018main/ADMBRO2018A_190218.pdf
Follow the brochure.