Is their any side effects of eating two wallnuts daily at moring while stomach is empty? is they are good and have healthy benefits or not?

No problems: Walnuts are a good food for snacks at any time although it is always good to have something in your stomach especially in the morning after s good nights sleep. Might be better to eat them after breakfast or at lunch or dinner time.

Healthy: source of fats, fiber and other micronutrients. And two has rather few calories so you are unlikely to run into problems with taking in too many calories. That can be a problem with many healthy foods, as there is always too much of a good thing!