I believe by Safety Officer you mean Safety Officer as per Factories Act.
The qualification of persons to be considered for appointment as Safety Officer will be notified by the concerned state governments as part of their Factories Rules. Normally, all industrial establishments employing 1000 employees are required by law to appoint a safety officer. However, if the state government is of the opinion, considering the hazardous type of operations involved therein, that a particular factory should have a safety officer, the government can issue such notification to such industrial establishment without considering the number of employees.
In Kerala Advanced Diploma In Safety Engineering is the basic qualification for Safety Officers. In Kerala this course is offered by the Supervisory Development Centre. The basic qualification for admission to this course is Degree in Engineering with three years experience in any factory or Degree in Chemistry with five years experience.
The system in other states may be different but there may not be much difference in it. I don't think that Degree in Nursing would qualify for admission to any Diploma in Safety Engineering. But please check.