you need evidence to substantiate your claim against the subordinate nursing staff who humiliated you because you are ST . instead of lodging FIR why dont you first write to management of your college regarding the obnoxious behaviour of the subordinate .

mention the name of witness es who were present . the management is bound to take action , conduct a inquiry against the subordinate . they will call upon the witnesses to give their version .

if no action is taken by the management then lodge complaint with police under prevention of atrocities against SCT /ST police will investigate your complaint . however you need evidence of witness to substantiate your statement .

in future when you face any such harassment record such conversations .

All are equal in the eyes of law. Any body can be a witness, if it is. It is always better to keep away from litigation.

Your sole statement is sufficient to initiate the legal process against the person who humiliated and insulted you by calling your caste. He can be prosecuted for calling your caste. Police may arrest him on the basis of your statement alone as it has nowhere been mentioned in law that a person cannot be arrested and prosecuted if nobody comes forth to record a statement against him. What will be the outcome of case cannot be told beforehand by any one. If the case is prosecuted with due diligence then the outcome may be favourable to you.