Can I opt for nios mathematics if iam a pcb student focusing on mbbs but little bit interested in engineering too

so guys actually since the day of my last boards exam I am extremely confused of stream selection well I heard many scl have already started cls 11 but mine is still 16 days away so the reason why Im writing this is to clear my doubt so basically I'm going to take pcb for mbbs pov but recently i have been getting interested in engineering too tho I don't wanna leave my mbbs plan but the problem is I think if I choose pcmb in cbse board it's too much headache so I came across nios so can I choose pcb in cbse and do maths in nios later or now only so that my options will still be available and one more doubt is that will it be same pressure to study maths separatly in nios as it is in studying in cbse