You can check NEST Syllabus at the oficial information bulletin at: https://nestexam.in/docs/20/NEST2020-Brochure-Syllabus.pdf . You can check about NEST 2020 more at our page: https://university.careers360.com/articles/nest

You can prepare from the following books:

Physics:

Concepts of Physics by HC Verma

Aptitude Test Problems by SS Kotov

Objective Physics by Mahesh Jain

Problems in Physics by AA Pinsky

Chemistry:

A Textbook of Organic Chemistry by RK Gupta

NCERT books

IIT Chemistry by OP Agarwal

Entrance Chemistry by Bhakta

Biology:

Objective Biology by Biswas and Biswas

NCERT

Elementary Biology for Class 12 by KN Bhatia

Mathematics:

Higher Algebra by Hall and Knight

Problems in Calculus of One Variable by I.A. Maron

Plane Trigonometry by SL Loney

Integral Calculus by Amit Agarwal