Dear Student,

Yes definitely you can score more than 90 marks in National Institute of Open Schooling (NIOS) if you are from commerce stream. It just requires your proper time management during the examination and how well prepared you are for the exam. In practicals you can secure good marks but in theory you require a good knowledge of the subject. So it totally depends on the candidate i.e. on you that if you want to achieve you can achieve it through hard work.
Best wishes!