nitro stalls after starting while in park?

There are a few components that can cause that same symptom. These Nitros are most notorious for throttle body failure but there is also a strong history of PCM (powertrain control module) and idle air control module failure that are consistent with your symptom. If this symptom is occuring very regularly I would recommend having the vehicle tested to verify where the issue lies. If the symptom is pretty random and doesn't occur regularly, unfortunately I would recommend letting the symptom become more regular so proper testing can be done to verify the failed component. hopefully that helps.