Hello Aspirant ,

No , You should not skip the whole NCERT book of Physics, Chemistry and Maths for JEE Mains as they are the basic books which help you clear your concept in a very easy way plus they contain hundreds of questions for your practice and sometimes you will find NCERTs question in JEE Mains .

If you have having some problem in some topics/chapter even then you should have a look of the chapter from NCERT .

Hope this helps.