Preheat your oven to 375°F (190°C).
Carefully slice the tops off the bell peppers and remove the seeds.
In a skillet, heat olive oil over medium heat and sauté minced garlic until fragrant.
Add chopped spinach to the skillet and cook until wilted.
Combine the cooked chicken, sautéed spinach and garlic, Parmesan cheese, Italian seasoning, salt, and pepper in a mixing bowl.
Stuff each pepper generously with the chicken mixture.
Place the stuffed peppers in a baking dish and cover with foil.
Bake for 25 minutes, then remove the foil and bake for an additional 5-10 minutes until golden.
Let cool slightly before serving.