Both Metallurgy at NIT Warangal and MSc in Biology at BITS Goa are great programs offering a plethora of opportunities and exposure to its students. But the choice between the two is a very personal matter as both the branches are very diverse in the opportunities they offer. So
However, you need to bear in mind the fact that BITS Goa is expensive and the fees is very high around 25 lakhs while NIT Warangal's total fees are less than 10 Lakhs.
One of my cousins recently encountered a similar situation where she had to choose between an M.Sc in Chemistry at BITS Hyderabad, and Biotechnology at NIT Warangal.
Thus, going for BITS Goa can be a superior choice to the NIT Warangal.