NIT

Yes. It is possible that you can get admission to a NIT with your current rank of 17781 in EWS category. You have a better chance of getting admission to a NIT with your current EWS rank. 

There is no such feature that converts other state seats of NITs to home state.Usually all seats are filled because for a home state student both the home state rank and the crl is considered. The system tires to fill these other state seats using the crl incase other state candidates is not available or is less or the seats are going vacant.

Hello,
Shiksha college predictor is the best technique to predict college based on JEE Mains score:

https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
Better results can be found here.
It produces accurate findings.
After that, simply go to that college's counseling.
Best wishes for the future.

The general category under economically weaker sections with such a good ranks of 15000 is so good. You can definitely take admission in computer Science in NITs or similar. Also option of IIT ROORKEE, IIT Madras and many more will be available so just go for it.

Your admission will depends upon other participants also. So no body can predict exact figure but for a very broad perspective I am providing you a basic idea for top ten nits ( any branch)

GEN- <35K+

SC-<110K+

ST-<225K+

OBC-<65K+

As you say you are from a ST category then I must say yes. You get a chance of having a lower NIT's or may be NITBhopal/kurukshetra if you are lucky.

Wait for 2nd and 3rd round, you'll definitely get any of the NITs.

Best of luck

Frankly speaking, chances for getting IITs, NITs and GFTIs are moderate on the percentile. You have to improve this up to 95 for more probability in upcoming JEE Main exams.

8000 begusaraik 8000 EWS rank