She's one year and six month she's has bronchitis and hard nose breathing is a problem for her please help me

Take her to a pediatrician...or any other doctor

Did a doctor confirm that he has bronchitis? How long has she been ill? As Smoothy said, take her to doctor if she seems very ill.

For general congestion, it can sometimes be helpful to use a humidifier (making sure to keep it clean), and using saline nose drops, with a nose aspirator if necessary. Slightly elevate the head of her bed if possible. Sitting with her in a steamy bathroom may help.

Do not give medication without checking with her doctor first.