Cut the tops off the bell peppers and remove the seeds and membranes. Place them upright in a baking dish.
In a large skillet, heat olive oil over medium heat. Add ground chicken and cook until browned, about 5-7 minutes.
Stir in garlic powder, onion powder, salt, and pepper, mixing well.
Add chopped spinach and cauliflower rice to the skillet, cooking until the spinach wilts and the cauliflower is tender, about 3-4 minutes.
Remove the skillet from heat and stir in 1/2 cup of mozzarella and Parmesan cheese, mixing until melted and well combined.
Stuff each bell pepper with the chicken and spinach mixture, packing them tightly.
Sprinkle the remaining mozzarella cheese on top of each stuffed pepper.
Cover the baking dish with aluminum foil and bake for 25 minutes. Then remove the foil and bake for an additional 10-15 minutes, until the cheese is bubbly and golden.
Remove from oven and let cool slightly. Garnish with fresh parsley before serving.
Notes
Feel free to use different types of cheese or add other vegetables.