Well you being an SC candidate, you have marginaly qualified the cut-off.

As JEE mains 2019 cut-off for an SC candidate was 54.012%ile and hence you have cleared by slightly over 1%age. By this percentile I'm suppossing you might not get any seat at NIT. 

But you have definitely cleared JEE mains and hence can appear for JEE advanced

I would advice you to study as hard as you can. 

Some necessary tips

• Go through all the previous year papers. Around 10-12 alike will definetely appear in your year paper too.
• Prepare the old subjective questions asked by JEE, especialy of math. They were really great concept building problems.
• Master Tip - prepare thoroughly for Inorganic chemistry. Around 35-40 marks of IOC come each year and you can secure atleast 30 from it provided you prepare well.

All the very best for your exams.