01 - Preheat oven to 375°F.
02 - Heat olive oil in a 10-inch ovenproof skillet over medium heat.
03 - Add red onion and bell pepper; sauté for 2 minutes until softened.
04 - Add zucchini and cook for another 2 minutes, stirring occasionally.
05 - Stir in garlic and spinach, cooking until spinach wilts, about 1 minute.
06 - Add diced chicken and cook for 1 minute to warm through.
07 - In a bowl, whisk together eggs, milk, salt, pepper, oregano, and thyme until well combined.
08 - Pour egg mixture evenly over the chicken and vegetables in the skillet.
09 - Sprinkle shredded cheese and Parmesan evenly over the top.
10 - Cook on the stovetop for 3-4 minutes until edges begin to set.
11 - Transfer skillet to the preheated oven. Bake for 12-15 minutes until the center is set and top is slightly golden.
12 - Let cool for 5 minutes before slicing and serving.