Trinanjana, 

I think BITS Hyderabad is better as Chemical Engineering is a core Branches and BITS being the brand name can attract many PSUs at the campus for placement and BITS has brand name. And in terms of education it is much better than VIT VELLORE. 

I know BITS Hyderabad is new it may create some doubt in your mind but I think for core branches it is better to join a college which has good faculty and academics and a brand name.