Both the colleges are good but as per Careers360 rating, NIRMA University has got AAAA which says this is a very good college overall whether you talk about faculty, facilities, hostel, placement, cut off trend, national and state ranking/rating, courses etc whereas PDPU has got AAA+ which means this is a good choice overall (above said factors) so as per my view NIRMA University should be your first choice and keep PDPU as the secondary option but also consider your choice, interest,convenience and eligibility before you make any decision.

To know more about both the colleges, you ca go through the below link-

https://engineering.careers360.com/colleges/nirma-university-ahmedabad

https://engineering.careers360.com/colleges/pandit-deendayal-petroleum-university-gandhinagar

Good Luck!!!!