Hi Anchal,
The pattern of PGI B.Sc nursing exam consists of 100 objective type questions from the subjects- PCB, ENGLISH and G.K. The paper will be of 100 marks. It will be a written test and not an online test. There will be negative marking of 0.25 marks for every wrong answer.  You'll have 25 questions each from PCB, 15 question from ENGLISH and 10 question from G.K/CURRENT AFFAIRS.
As time is less for this exam now, you can revise your 10+2 PCB books thoroughly. English part will be basic so you'll be able to attempt but still you can go through some comprehension, vocab online and revise a bit. For G.K you can go through once from the last 6-8 months important news updates from any newspaper or through some websites, online.
For more preparation you can refer to books like: R.Gupta's General Nursing,  Arihant General Nursing Guide,  Competitive guide for Nursing exams by R.S Sharma,   Competitive Handbook for Nursing and   TPG B.Sc Nursing guide. 

Hope this helps, good luck!