Hey.

The cut off for the previous year of Tamil Nadu NTSE was 127 marks out of 150 in 2018 and 120 marks in 2018. You can expect a similar range this year. The cut off may vary year to year according to various factors like level of exam, no of candidates etc. The maximum marks this year is also 200  unlike previous year.  You can use the link below to check the previous year trends.

Https://www.google.co.in/amp/s/school.careers360.com/articles/ntse-tamil-nadu-cutoff/amp
Best of luck!