You can download the NBSE question papers of class 12th by clicking on mentioned below link which I am providing. The link contains previous year question papers from 2020. You need to do just that click on the link which is mentioned below and a scroll down and you will see a list of all the subjects along with the links. These subjects include

• alternate English
• English
• Science
• Social Science
• Mathematics
• bookkeeping and accountancy
• Home science
• environmental education

https://www.google.com/url?sa=t&source=web&rct=j&url=https://school.careers360.com/boards/nbse/nbse-hslc-question-papers/amp&ved=2ahUKEwiV8fDPgJf1AhWw73MBHWiZAlgQFnoECAQQAQ&usg=AOvVaw13ek4-UyOgDDEjGkle6xwM