The infrastructure of a college is one of the major concerns for a fresher but after a year it doesn't matters much as a good infrastructure doesn't mean that it will provide you with good placements.
Now, as far as the infrastructure is concerned NIT Manipur won't be able to live up to your expectations as it is a newly formed NIT. The campus is not as beautiful and modern as you would expect from other NITs.
As it is a newly growing college, the temporary campus has currently shifted to the permanent ground and the construction work is still going on there.
But apart from infrastructure, the faculty and placements of this college are very good and you should consider this college as a valid option.