Preheat the oven to 375°F (190°C).
In a large skillet over medium heat, add the olive oil and chopped spinach. Sauté for about 2-3 minutes until wilted.
In a mixing bowl, combine the sautéed spinach, dried cranberries, cream cheese, mozzarella cheese, garlic powder, onion powder, salt, and pepper. Mix well until all ingredients are combined.
Place the chicken breasts on a cutting board. Using a sharp knife, make a pocket in each chicken breast by slicing them horizontally, being careful not to cut all the way through.
Stuff each chicken breast with the spinach and cranberry mixture, using toothpicks or kitchen twine to secure the openings.
Place the stuffed chicken breasts in a baking dish and bake in the preheated oven for 25-30 minutes, or until the chicken is cooked through and no longer pink in the center.
Once cooked, remove from the oven and let the chicken rest for 5 minutes before serving.