Hello dear, 

Nest exam includes your physics , chemistry , biology and  maths out of which you have to anwer any three out of them and even if you answer all the four then only three out of them with highest marks is counted. And it also contain general aptitude section and questions are mainly to quite tough and are mainly data based . Its quite tough and you can consider its level between that of jee mains and jee advance but go through the link given below to download past year papers of nest exam and you can check yourself level of questions asked in exam .

https://www.nestexam.in/

Thankyou 

Please feel free to ask your further queries if any.