Preheat oven to 375F degrees.
Spray a 9×13 casserole dish with cooking spray.
Rub minced garlic over each chicken breast and season with oregano, Italian seasoning, salt and pepper.
Transfer chicken to casserole dish, lightly spray with cooking spray, and bake for 15 minutes.
In the meantime, prepare the spinach topping.
Heat olive oil in a skillet; add spinach and cook for 2 minutes, or until wilted.
Remove spinach from heat, stir in the cream cheese, and season with salt and pepper; stir until softened.
Take chicken out of the oven, flip over each chicken breast, and layer the spinach mixture over each piece.
Top with shredded mozzarella and feta cheese.
Bake for an additional 20 minutes, or until cheese is melted and browned on top, and chicken is cooked thoroughly.
Remove from oven and serve.