Oxidation states range from #N(-III)# to #N(V+)#......
Explanation:
Nitrogen is #-III# in ammonia, and #+V# in #NO_3^(-)#. We have #N(+II)# in #NO#, and #N(+IV)# in #NO_2#. Nitride anion is #-III#, and nitrogen is #-II# in hydrazine, #H_2N-NH_2#. Of course the common oxidation state is #0# in #"dinitrogen"#.