See, according to the cut-offs of the previous years you have qualified the joint entrance examination. However, if you do better than this in Joint Entrance Examination Advanced, then you won't be getting a seat in National Institute of Technology, as NITs take admission through JEE Main, and even if you top the JEE Advanced examination, you won't be getting any NIT on your score of JEE Advanced.

Hope I have answered your question. All the best!