It sounds to me like your haveing some other issue for sure...

As far as Nitronizeing:

All of my vehicles are NITRONIZED.. I purchased and have a road hazard warranty thru Belle Tire. The one thing I have noticed useing nitrogen... I have fewer rim leaks!
Im not sure what contributes more:
The Nitrogen or the maintenance? I regularly rotate my tires every 3000 miles. and Obviously when they do the rotation they also check tire pressures and maintain them.

I will say this...as an example...
I have 25,000 mile tires that have well over 60,000 miles on them..

I will say I believe haveing them Nitronized helps.
Supposedly, Nitronizeing is suppose to help eliminate rim leaks, as well as improve fuel mileage...Maybe thats why my Z-71 Silverado gets such great fuel mileage towing my 28 ft 5th wheel camper?