Any candidate with an Indian Citizenship can appear for the NEET examination.
Be it be an NRI ( Non Resident Indian), an OCI cardholder or any other resident of the country.
The person should fulfill the eligibility criteria of the exam i.e, the defined age limit , the score of 12th class or equivalent , subjects required etc.
Not only can an NRI appear in the exam, but in many states ( subject to variability ) , they are also provided an NRI quota in many private as well as government colleges.
Currently, the Medical Council of India reserves 15% quota for NRI students which includes both Persons of Indian Origin (PIO) and Overseas citizen of India (OCI) card holders.