Hey.

No it is not possible to join NLUs to pursue law after graduation. As NLUs only offer 5 year Integrated courses of law which combine Undergraduation course with law. And after graduation a 3 year LLB course is a suitable one which is not offered by any NLU.

Hence after graduation the most sought after law entrances for 3 year LLB course are-

DU LLB - Delhi University 

MH CET- GLC mumbai, ILS Pune and other colleges in Maharashtra 

SLAT- Symbiosis Law school

PU LLB- Panjab University, Chandigarh 

LSAT- Jindal Global Law School, IIT Kharagpur 

BVP LLB, BHU LLB etc.

Best of luck!