Yes, you can pursue an MBBS abroad after completing your 12th grade through the NIOS board with PCB (Physics, Chemistry, Biology) subjects, as long as you meet the following criteria:

1. NIOS Eligibility: You need to successfully complete your NIOS 12th exams with PCB subjects. Ensure you register for the NIOS exams for the 2024-25 academic year.

2. NEET Requirement: Most countries require you to qualify for the NEET (National Eligibility cum Entrance Test) for admission to medical colleges. Make sure to prepare and appear for NEET.

3. Universities Abroad: Many countries, such as Russia, Ukraine, China, and the Philippines, have universities that accept NEET scores for MBBS admissions. Research universities in these countries to find suitable options.

4. Application Process: After qualifying NEET and completing your NIOS exams, you can apply to universities abroad. Each university will have its own admission process and requirements.

In summary, with your NIOS 12th completion and NEET qualification, you can pursue MBBS abroad. Make sure to check specific university requirements for admission.