For those with nasal only bad breath

I asked Google

can LPR smell come out the nose only

Yes, LPR (laryngopharyngeal reflux) can cause a bad smell that is primarily or exclusively detected in the nose. Stomach acid and gases can travel up the esophagus, bypassing the throat to enter the nasal passages and sinuses, causing a sour, acidic, or foul smell to be perceived, often accompanied by nasal congestion.