As a commerce student,You are not eligible to take BTech.It is not possible to do Bachelor of Technology when you have completed your class 12 with commerce stream.But the commerce of CBSE  and two year syllabus of science of NIOS Board is same.So you can surely appear physics and chemistry in NIOS.The marks of the rest of the subjects will transferred from previous board's marksheet to your new NIOS marksheet through transfer of credit system.Then you can apply for BTech by appearing Entrance Exam.