Evening John,
It depends on how the MN has occurred in the first place, and that it is actually a MN (there are other differential diagnoses dependent on your symptomology). Wider footwear (several sources have been mentioned above) should alleviate the problem if it is purely due to lateral compression, allowing the irritated nerve to reduce in size over time. If not, again as suggested above, a metatarsal dome (pad), situated in the midfoot, behind the met heads has been found to be beneficial as this allows for splaying of the joints, again reducing the pain. But beware, some patients find that this increased pressure on the plantar surface can actually make their symptoms worse. This is where I find that a cut out works better, but it depends on the patient and how mobile their forefoot is. If not, you can always try a cortisone injection, but to confirm your diagnosis get them to give you a local anaesthetic first - if your symptoms go away, then you're spot on.
Try that and see how you get on.
Ablefeet 