Prep the peppers: Preheat the oven to 400°F (200°C).
Slice the bell peppers in half from stem to base and remove seeds and membranes. Place them cut-side up in a baking dish. Drizzle with a little olive oil and season with a pinch of salt.
Soften the peppers (optional but helpful): Add 1/4 cup chicken broth or water to the baking dish.
Cover tightly with foil and bake for 10 minutes to start softening. Remove and set aside while you make the filling.
Sauté the aromatics: Heat 1 tablespoon olive oil in a large skillet over medium heat. Add the onion and cook 3–4 minutes until softened.
Stir in the garlic and cook 30 seconds until fragrant.
Brown the chicken: Add ground chicken, breaking it up with a spatula. Cook 5–6 minutes until no longer pink. Season with taco seasoning, a pinch of salt, and black pepper.
Add moisture and mix-ins: Stir in the salsa.
If using, fold in black beans, corn, and cooked rice or quinoa. Simmer 2–3 minutes so flavors come together and mixture thickens slightly.
Add cheese: Remove from heat and stir in 1/2 cup shredded cheese until just melted and distributed.
Stuff the peppers: Spoon the chicken mixture evenly into each pepper half, mounding slightly.
Top and bake: Sprinkle the remaining 1/2 cup cheese over the stuffed peppers. Cover the dish with foil and bake 15 minutes.
Uncover and bake another 10–12 minutes, until peppers are tender and cheese is bubbly and lightly golden.
Finish and serve: Let rest 5 minutes. Garnish with cilantro or green onions. Serve with lime wedges and your favorite toppings.