Getting your NIOS hall ticket is a fairly simple procedure. There are two ways in which you can do this, first is using their (NIOS) web service and the second one is to use their mobile service. Check the corresponding sub headings to know the procedures for both.
Web hall ticket retrieval
And for study centres looking for hall tickets, they can follow these links:
Mobile hall ticket retrieval
For Secondary (Class Xth students)
NIOS10 <your rollno> and send it to 5676750
For Sr. Secondary (Class XIIth students)
NIOS12<your rollno> and send it to 5676750