Your rank can be predicted by using the formula, (100-your total percentile)*869010/100. In your case, your approximate rank would be 61786. This is your overall rank and not your Category rank. Let's say the number of candidates for April exam increased to 12,00,000 then your final rank shall be (100 - your total score) X 12,00,000/100.You can check NIT's previous year cut offs at our page: https://engineering.careers360.com/articles/jee-main-cutoff-for-nit-delh

Going by this, you might have decent chance at NIT Delhi.