Which is better for mechanical engineering - the NIT in Calicut or BITS Goa?

If you are fine with the higher fee structure of BITS Goa, then it will be a better choice for you. The infrastructure of both colleges is similar to each other but the alumni network is better at BITS Goa compared to NIT Calicut. 

But if you are interested in mechanical engineering and want to pursue it as your passion, then you should probably choose NIT Calicut. The placement records of the Mechanical department in core companies are better at NIT Calicut. The average package offered is also higher than BITS Goa. Many students opt for jobs in non-core companies especially in the IT sector from BITS Goa and they learn coding too during their graduation. 

If you are looking for a job related straight to what you have studied, then choose NIT Calicut. However, if you have a plan to go for higher education, probably abroad, then BITS Goa will be a better choice. Its alumni network will also help you a lot in securing a job in a reputed company.