Why does my nose feel congested in the morning?

Normal. While we sleep we produce less adrenaline in our body. Adrenaline is a natural decongestant. This is why the stuffiness goes away after being awake for an hour.
Possible reasons for. A.M. Nasal congestion include: if you sleep lying flat in bed, this gives mucus a chance to pool in your nasal passages. While you are sleeping the mucus thickens & you wake with congestion. If the air is dry in your home this can contribute to thickening of the mucus. Are you allergic to dust mites? They infest your pillows, mattress and bed linens leading to allergic reactions in some people.