Cook the diced chicken breast in a frying pan over medium heat until fully cooked.

Add olive oil to the same pan and sauté the onion until it becomes translucent.

Add tomatoes and spinach to the pan and sauté until slightly softened.

In a separate bowl, crack the eggs, add salt and black pepper, and mix well.

Pour the egg mixture over the sautéed ingredients in the pan and cook with the lid on over medium-low heat.