Hey,

Below I have attached a link that you can refer to fir more detailed information regarding your question. Refer to it for more help.

https://university.careers360.com/articles/jnu-syllabus

For summary, No it's not a necessity to have Chinese in your 10+2 if you want to pursue BA in Chinese from JNU. In the entrance exam they ask questions from section that comprises of, English, General Knowledge, Artificial language and Reasoning.

Buy some past year question paper for the exam in order to decode the important topics for the exam.

Hope that helps.

All the best.

Thank you.