B. E. Douglas, D. H. McDaniel, J. J. Alexander, Concepts and Models of Inorganic Chemistry, 3rd edition, John Wiley & Sons, New York, 1994, page 196.

Problem 4.6

Write the MO configurations (e.g., 1s2 for H2) and give bond orders of NO+, NO, and NO-. Which of these species should be paramagnetic?

Answer:

Use Table 4.1 and adapt for the number of electrons.
  Electron Configuration
Bond Order
Unpaired Electrons
NO+ 2s22s*2 pz2x,y4 x,y*0
3
0
NO 2s22s*2 pz2x,y4 x,y*1
2.5
1
NO- 2s22s*2 pz2x,y4 x,y*2
2
2

NO and NO- should be paramagnetic.