Chronic Bronchitis: This condition is characterized by the production of excess mucus, leading to a chronic cough that is often worse in the morning and at night. The symptoms described align closely with the typical presentation of chronic bronchitis, making it the most likely diagnosis.

Asthma: Asthma can cause coughing and the production of thick mucus, especially at night and in the morning due to the natural circadian rhythm of asthma symptoms.
Allergic Rhinitis: Postnasal drip from allergic rhinitis can lead to a cough, particularly in the morning and at night, as mucus accumulates and irritates the throat.
Gastroesophageal Reflux Disease (GERD): GERD can cause stomach acid to flow up into the throat, leading to irritation and a cough, which may be worse at night and in the morning due to lying down.

Pulmonary Tuberculosis: Although less common, tuberculosis can present with chronic cough and mucus production. It's crucial to consider this diagnosis, especially in individuals with risk factors such as exposure history or immunocompromised states.
Lung Cancer: A persistent cough with mucus production, especially if accompanied by other symptoms like weight loss or hemoptysis, necessitates consideration of lung cancer, despite its lower likelihood.
Cystic Fibrosis: In younger patients or those with a family history, cystic fibrosis should be considered due to its severe implications and the need for early intervention.

Bronchiectasis: A condition characterized by damaged airways, leading to excessive mucus production and chronic cough. It's less common but should be considered in patients with recurrent infections or specific risk factors.
Primary Ciliary Dyskinesia: A rare genetic disorder affecting the cilia in the respiratory tract, leading to chronic respiratory infections and cough. It's an important consideration in patients with a suggestive family history or recurrent sinus and lung infections since childhood.