Dear Sonali, there are quite a few Institutions offering Post Basic B.Sc Nursing. Few Institutions have started the application process. And every Institution has its own criteria. Few Institutions conduct admissions based on merit in 10+2 while few Institutions conduct admissions based on Entrance Examination. The colleges might tentatively commence their classes somewhere from May/ June. So if you have any particular Institution/State in mind, do let us know so that we can give you the pertaining information. 

Dear Aspirant,
The last phase of registration will begin on March 14,2019. 
AIIMS will conduct exam the entrance exam for admission to the courses on June 1, 15 and 23 ,2019. Admit cards will be released on May 16,2019.
Candidates who have cleared class 12 Senior School Certificate Examination or Intermediate Science or an equivalent examination from a recognized University/ Board of any Indian State with English, Physics, Chemistry and Biology and has minimum aggregate marks of 55% can apply for B.Sc.
Nursing (Honours) For B.Sc. paramedical courses, candidates must have cleared 10+2 in English, Physics, Chemistry and either Biology or Mathematics with 50% in aggregate.
For the B.Sc. Nursing (post basic) course candidates with Diploma in General Nursing and midwifery and registration as nurse, (registered nurse, registered midwife can also apply.
Hope this helps you.
All the best.
Comment down for any queries.