Dear Rahul 

If you are talking about NCHM Counselling 2018, then as per the rules, if you didnt register for first counselling round, then you will not be able to registerf ro second round, however, you can definitely apply and register in the third counselling round of NCHM. Fresh registerations will be allowed in the third counselling. 

So, provided you qualified the exam, you can register online at NCHM Online Counselling Portal. 

Hope it helps. 

All the best!