see, NT stands for Nomadic Tribe. So NT1, NT2 and NT3 are Categories of Nomadic tribes listed in Maharashtra Caste . list. Maharashtra MBBS seats are filled through 15% All India Counselling and 85% State Counselling. The State Quota seats are filled divided into 70% Regional quota and 30% State Quota. The 70% Regional quota seats are reserved for Candidates belonging to Vidarbha, Marathwada and Rest of Maharashtra. And the Constitutional quota of Maharashtra is for Candidates belonging to SC, ST, Vimukta Jati/Denotified Tribes, NT-A,B,C,D and OBC.
you will now be able to decide the category.
hope that helps