NITs of India are the some of the best engineering institutes in the country, right after the IITs. And as such, getting an admission into an NIT is nothing short of a Herculean task given the competition level in India.
To get into NIT Goa for an UG score, you need to appear for JEE Main. The closing rank for BTech CSE was 10,587 for the year 2019 (General Quota). Hence, you can see that you need to stand out and secure a really high rank in order to get in NIT Goa.
The basic eligibility criteria for a BTech course in NIT Goa is that a candidate must finish their 10+2 from a recognised board in the science stream with a minimum aggregate of 75% with Physics, Chemistry and Math as the core subjects.
Hope this information helps
Best of luck!!