I got low marks in CUET, but my UG marks and board marks fit the eligibility criteria. Is there any way I can get into NIT?

No, NIT admissions are not based on CUET scores. NITs accept only JEE Main scores for UG courses such as B.Tech. No matter how well you've done in your Class 12th board and have fulfilled the eligibility criteria, CUET is not acceptable for NIT admission.

Here’s what you need to know:

If your goal is to get into an NIT, appearing for JEE Main is a must.
 

If you have performed decent in CUET, you can attempt to get admission to top central universities and other colleges that accept CUET scores for B.Tech or other undergraduate degrees.

 – Delhi University (DU)
 – Banaras Hindu University (BHU)
 – Guru Gobind Singh Indraprastha University
 = Aligarh Muslim University and similar institutions.