Metaldog· I work so I can... SQUIRREL!
Does your Nitro have a sunroof? There are drain holes at the front of the sunroof on both corners that can get clogged with debris. A rubber hose is connected to each drain hole and runs down the a-pillar, and out on the underside of the vehicle. It is possible that one of the rubber hoses is leaking and has allowed water to get in behind the dash. Just a shot in the dark, and mainly guessing, but that could be a possibility.