You want to be shooting more or less dead on to the subject, not to the side. The rule of thumb is that the line of the nose should not 'break' the line of the cheek, and this is doubly true for nasally well-endowed subjects.
Avoid wide-angle lenses like the plague - you need to be looking at a 100-135mm lens ideally, as it will flatten the photograph somewhat.
Lighting should be very soft to prevent the nose casting tell-tale shadows. A large softbox is ideal, or if you are using natural light try fixing a thin white cloth or paper to a window to soften the light right down.
EDIT: Since you've mentioned that the subject's nose is wide, I would disregard the first point and instead shoot from an angle. I'll leave the answer as it is otherwise so both wide and long noses are catered for :)