Is 7 months of preparation enough to get admission in NLSIU? What is a book list for all subjects?

Without any doubt, 7 months are enough for the preparation of CLAT, but it depends totally upon the hard work and efforts that you are going to put. You should refer to some original books instead of the coaching material solely. 

For English, you can refer to banking books and WPM, for Maths and Logical Reasoning refer to CAT preparation books. Read newspaper daily for a comprehensive General Knowledge. For Legal refer to the coaching material or some legal guides from Amazon.

Thus, by studying from the books mentioned above you can score quite well in your exam.