Exhaled nitric oxide measure of 75 ppb today. could that cause light headedness, dizziness, fatigue or memory issues?

No: Exhaled nitric oxide is used to determine the level of control of one's asthma. It's usefullness for diagnosing other conditions is limited. The FeNO being elevated (and 75 ppb is elevated) is probably not the cause of your symptoms unless your asthma is poorly controlled and causing those symptoms.

Nitrous oxide exposu: Inhalation of nitric oxide can be deadly if exposed for long periods of time. The symptoms are usually temporary and not long acting. Again this presumes you were not in a chamber breathing it in for a long period of time. I do not think you were likely exposed for a long period. The fatigue and memory issues could be the anxiety of the unknown situation. Try to find out the duration.

Mgt and workup: I would suggest a follow up visit with you lung specialist, pulmonary function testing, a total IgE, CBC with differential as part of your workup. Your physician will help you identify allergic triggers and suggest how to lower your exposure to allergens. Your symptoms may be related to respiratory difficulty.