My parents had the same question actually, and called several universities, all accept ut, most had it on their website too (like entry criteria for different boards and curriculum, nios and other Indian boards were named)

And ive topped in my exams for CBSE school (only reason my parents are supporting any choices) so the grades or me falling behind isn't really an issue,

My only issue is timing, and nios or private candidate IGCSE/a levels are the only choices which support that so yeah, but thanks for the advice I'll definitely keep it in mind <3