Hi Tanushree, 

With category rank of 3K, you could easily get into any NIT however there are certain factors which will affect your admission.

• The branch of your preference
  
• Your home state

Both of these factors will affect your rank in the same order. If you are aiming for branches like Computer Science or Mechanical or ECE, then surely you will find it hard to make into any top 10 NIT, however, if you could settle for lower branches like Civil, chemical or metallurgy then surely you could get into any of them.

This is the complete list of all the NITs with their cutoff.

https://engineering.careers360.com/articles/nits-cutoff-for-top-btech-branches

Thank You.