Hi dear,
The fee structure of the NITs is set by the MHRD in consultation with the NIT Council. Consequently, the tuition fee is the same across all NITs, which is Rs. 62, 500 per annum. But for some other components the fee structure may vary.
There are other components like Lab and library deposit fee, Alumni Association fee, and Magazine Fee that may differ from one one NIT to another.
Also, the fee structure for a candidate may vary in an NIT depending on the candidates category and/or annual family income.

Click on the link below for more details..
https://engineering.careers360.com/articles/nits-btech-fee-structure


Hope this helps