Preheat the oven to 375°F.

Cut the tops off the bell peppers and remove the seeds and membranes. Lightly brush the outside of the peppers with olive oil and place them upright in a baking dish.

In a large skillet over medium heat, add the olive oil and sauté the diced onion and minced garlic until the onion is translucent, about 3-4 minutes.

Add the ground turkey to the skillet and cook until browned, breaking it apart with a spatula, about 5-7 minutes.

Stir in the cooked rice, diced tomatoes, chili powder, Italian seasoning, salt, and pepper. Mix well and cook for an additional 2-3 minutes until heated through.

Spoon the turkey mixture into each bell pepper, packing it tightly. Top each pepper with shredded cheese.

Cover the baking dish with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and the peppers are tender.

Remove from the oven and let cool for a few minutes before serving.