Chronic rhinosinusitis (CRS), a prevalent inflammatory illness, affects a sizeable portion of the global population. An important component of the upper respiratory system, nitric oxide (NO) controls inflammatory responses and functions as an antibacterial, antiviral, and antifungal agent. The enzymes arginase (ARG) and inducible nitric oxide synthase (iNOS), whose activity has been linked to a range of respiratory disorders, generate NO. N-acetylcysteine has demonstrated potential as a CRS treatment option. The present study aimed to evaluate the levels of iNOS, ARG, and constitutive isoforms of NO-synthase in sinonasal fluid at multiple time points after surgery. Significant differences were observed in the levels of iNOS, ARG, and constitutive isoforms of NO-synthase between the two groups after treatment. The experimental group, receiving topical N-acetylcysteine, exhibited increased iNOS activity on the 3rd day, followed by a decline on days 10 and 28. Similarly, ARG activity increased on day 3rd in both groups but was lower in the experimental group at later time points. The findings suggest that NO-related enzymes, particularly iNOS and ARG, play a crucial role in the pathophysiology of chronic rhinosinusitis without polyps. Additionally, topical N-acetylcysteine treatment seems to affect NO production and ARG activity, which may help to reduce inflammation and enhance clinical results. These results highlight the therapeutic potential of N-acetylcysteine in managing chronic rhinosinusitis and warrant further investigations into its broader implications for respiratory conditions. For patients with CRS without polyps, adding N-acetylcysteine to the treatment regimen may result in more focused and efficient therapeutic strategies.