Hello, 

Tamil Nadu board has set some criteria for nativity/domicile certificate. They are as follows-

1. Student should must be a native of the state.

2. Permanent residence certificate in place of nativity certificate will not be accepted.

3. Candidates who are native of Tamil Nadu but have finished there schooling ( class 6 to class 12) completely/partly from some other state should present a certificate showing date of birth of student in the state and also it should show students relation to his parents. 

So I am sorry to inform but you are not eligible for applying from Chennai in NEET. 

For any further information regarding this you can refer to careers360 link.

https://www.google.com/amp/s/medicine.careers360.com/articles/tamil-nadu-mbbs-admission/amp