Sensor shinobi in the Narutoverse is defined as the person who can feel Chakra specifically through his/her own Chakra. Smelling can be referred as sensing, however in Kiba's case, he is only using it to track. Sensing involves being capable of feeling the presence through physically and mentally in which be Chakra sensors. Kiba is sensing only physical stuff.
I wouldn't call him exactly a sensor as he doesn't apply in Narutoverse. He is more of tracker instead.