NATA comprises of Perspective drawing, 2D, 3D and aesthetic sensitivity test. So there is no ideal book from where you can learn and the questions have no fixed pattern as they keep on changing. So don't just refer one book but, go through all books (or at least as many as you can). If there is something that you don't understand for example shade shadow, toning, different types of perspective drawings then you can also refer YouTube videos for reference.

Its always better to be a step ahead, so read a lot about up coming buildings, architects, material used, etc.

I'll list a few books which you can refer to :

NATA & B.Arch Question Bank  by Ar. Shadan Usmani

NATA & B.Arch complete self study material: entrance examination by  Ar. Shadan Usmani

A Complete Self Study Guide for B.Arch by P. K. Mishra

B.Arch Entrance Examination Guide by Surendra Kavimandan

Some coaching institutes also provide a full set of self study books. I'm adding a link to two such coaching institutes:

NATA Study Material and Online Test Series

Buy Nata Entrance Books online- Mosaic Institute of Design