Yes, it is possible to apply for a fresh Class 12 (Senior Secondary) certification through NIOS, even if you have already passed Class 12 from CBSE earlier, and you do not have to opt for Improvement or TOC (Transfer of Credit) if you do not want to carry forward any CBSE subjects.

NIOS allows candidates to enroll for Senior Secondary Course (Class 12) as a fresh candidate , regardless of their previous board results, provided they have passed Class 10 from a recognised board. Since you completed your Class 12 in 2018 and your marks are low, you can choose to start afresh with NIOS, select new subjects, appear for examinations, and obtain a new NIOS Class 12 marksheet with improved scores. In this case, your earlier CBSE Class 12 marksheet will not be cancelled or deleted (no board ever “erases” an earlier qualification), but you are free to use only the NIOS marksheet for future admissions, jobs, or eligibility purposes, as long as the institution accepts NIOS.

Choosing “without TOC” simply means you are not transferring any CBSE marks and will be appearing for all subjects again under NIOS. This is often the best option for students who want a clean restart and significantly better scores. NIOS is a government-recognised board (under the Ministry of Education), and its certificates are accepted by most universities, colleges, and competitive exams in India, including for graduation, professional courses, and even some government jobs (subject to specific eligibility conditions).

Before enrolling, make sure to carefully select subjects relevant to your future plans and confirm acceptance criteria with the universities or exams you are targeting. But overall, yes—you can completely rely on NIOS for a fresh Class 12 marksheet without improvement or TOC, and this is a common and valid route for students in situations similar to yours.