Refers to someone who keeps watch during the night.
El nochero vigilaba la entrada del edificio toda la noche, asegurándose de que todo estuviera en orden.
The night watchman guarded the entrance of the building all night, ensuring that everything was in order.
El nochero caminaba por las calles vacías mientras la luna iluminaba su camino.
The night watchman walked through the empty streets while the moon illuminated his path.