Hi Kiran,

Yes, if you didn't get any seat till 2nd round of aiims nursing then, you can appear for the open round of counselling again.

But in this, your chances of getting a seat is like 50-50% because your sadmission now depends upon the highest cutoff and seat availability during this open round of counselling. 

Still I will suggest you to apply for this and hope for the best. 

Good luck.