M.Sc Eligibility

Yes, definitely, after completing B.Sc Nursing, you are eligible for a Masters course in Forensic Science.
Forensic Science Masters courses-M.Sc. (Forensic Science & Criminology)M.Sc. (Forensic Sciences)M.Sc. (Information Security and Cyber Forensics)
Eligibility Criteria:
Applicants must hold B.Sc. degree (10+2+3 system of education) in any Science subjects- any combination with at least 50% marks or equivalent CGPA.
Forensic Sciences Masters course job titles-Forensic PsychologistCompliance OfficerCorrections OfficerCustoms AgentPolice Detective, Police OfficerCrime Scene InvestigationPrivate Security, Private InvestigatorForensic Medicine ProfessorCoast GuardSecret Service

For M.Sc, there is something called JAM exam.
You can get more information here:
http://jam.iitm.ac.in/jam2016/ac
The candidates who qualify JAM 2016 shall have to fulfil the following eligibility requirement (ER) for admissions in IISc and IITs. All candidates admitted through JAM should have a Bachelor's degree. At least 55% aggregate marks, without rounding off, (taking into account all subjects, including languages and subsidiaries, all years combined) for General/OBC-NCL category candidates and at least 50% aggregate marks, without rounding off, (taking into account all subjects, including languages and subsidiaries, all years combined) for SC/ST and PwD category candidates
in the qualifying degree. For candidates with letter grades/CGPA (instead of a percentage of marks), the equivalence in percentage of marks will be decided by the admitting institute (s).