Hello aspirant,
Bachelor of Science in Nursing or B.Sc Nursing is a 4-year undergraduate course. B.Sc Nursing admission is based on entrance exams held between April-June.The minimum eligibility criterion for pursuing this course is the successful completion of 10+2 level of education in Physics, Chemistry, and Biology.
B.Sc. Nursing admission is purely based on entrance exams held between April-June. Candidates can fill the application form in both online and offline mode.Many colleges in India offer this course as a branch of medicine. Some of the top colleges are mentioned below.

• Christian Medical College, Vellore
• Sri Ramachandra University, Chennai
• KLE University, Belgaum
• Symbiosis International University, Pune
• Sharda University, Greater Noida
• Bharati Vidyapeeth Deemed University, Pune

The admission are almost done in most of the colleges, though I'll suggest you to personally visit few colleges which might help you to get a seat. Or join some private college which has direct admission.
All the best