Both are good colleges. Nirma being in Ahmedabad ,and Christ College in Bangalore (gives Christ a better edge over Nirma) But Nirma is great as placement in the college is good. Both college has record placement.
It depends on individual how s/he grooms her/himself . Placement are good at both . You have to take one job that you can get from both the college if you perform well.
Try to work on your personality , read good books. Be fearless whatever you do.