Viral Upper Respiratory Infection (URTI): Given the age of the patient, symptoms of cough and runny nose, and the presence of sick contacts at home, a viral URTI is the most likely diagnosis. The high heart rate (HR of 192) can be seen in infants with viral infections due to their smaller heart size and higher baseline heart rates compared to adults.

Bronchiolitis: This is a common lower respiratory tract infection in infants, often caused by the Respiratory Syncytial Virus (RSV). The symptoms can start with upper respiratory tract symptoms like runny nose and cough, progressing to lower respiratory symptoms.
Influenza: Although less common in this age group without specific exposure history, influenza can cause similar symptoms and should be considered, especially during flu season.

Congenital Heart Disease: While the infant had no complications during delivery, a high heart rate can be a sign of congenital heart disease, especially if associated with other symptoms like poor feeding, sweating, or difficulty breathing.
Sepsis: Neonatal sepsis is a serious condition that can present with non-specific symptoms including respiratory distress, fever, or hypothermia, and tachycardia. It's crucial to consider sepsis in any neonate with concerning symptoms.
Pneumonia: Bacterial pneumonia can present with similar symptoms and is a critical diagnosis not to miss due to its potential severity and need for antibiotic treatment.

Cystic Fibrosis: Although very rare to present this early, cystic fibrosis can cause respiratory symptoms due to thick mucus production. However, it would be unusual for this to be the first presentation of the disease.
Primary Ciliary Dyskinesia: A rare genetic disorder affecting the cilia, leading to chronic respiratory infections. It's unlikely to be diagnosed at this age without a family history or other suggestive symptoms.