Not blowing hot air out of heater vent , motor working on all settings both matrix pipes are warm when car is at operating temperature
The most likely issue is with what is called the "blend door" actuator. The blend door is a movable door that mixes the air from 100% cold to 100% hot as you adjust the temperature control. In some cars this is just a cable but today it's usually an electrical or vacuum operated motor. These are tiny things and they wear out and break over time.
It's not clear what year your Nissan is but this page:
Shows the part for some years: