Hey Srithan ,
Greetings!

Yes , you can definitely get admission in Delhi University for Bsc. Chemistry course . However , You have include Mathematics in the best 4 subjects because eligibility for B.Sc Chemistry includes Physics, Chemistry , Mathematics and One Language course.
That clearly means you cannot add CSE in best 4.

Hope this will help . Good Luck ! You can reply to this comment if you have any further queries , I will be happy to help .