There is no such admission like CBSE for the students who have already appeared for examinations from another board. However, if you want to give Biology exam from NIOS board, then you will have to first register on its website as a private candidate. After completing all the registration formalities, you will get to select the exam date and center as per the availability and as per choice.

For more information, you may visit the following website:

www.nios.ac.in (//www.nios.ac.in)