Hi,
Bsc nursing admission is done on the basis of merit of entrance exams. Universities such as Delhi university give admission to candidates on the basis of their marks in class 12th while several other colleges conduct entrance exams.
Some of the popular entrance exams in bsc nursing are AIIMS bsc nursing entrance exam , MNS entrance exam , JIPMER , BHU UET , etc.
Application forms are generally released in the month of april to June.
Hope it helps...