Preheat the oven to 425°F (220°C) and prepare a rimmed baking sheet by lining it with parchment paper. Set it aside.

Slice the poblano peppers in half lengthwise, removing the ribs and seeds. Arrange the peppers cut side down on the prepared baking sheet. Lightly coat them with olive oil and roast for 8 minutes. After roasting, reduce the oven temperature to 350°F (175°C).

While the peppers are roasting, heat a large skillet over medium heat. Cook the ground beef, breaking it apart as it browns. Add the diced onion and minced garlic, and sauté until the onion becomes tender, approximately 5–7 minutes. Drain any excess grease from the skillet. Season the mixture with chili powder, cumin, paprika, and kosher salt.

Incorporate the cooked rice, black beans, tomato sauce, green chiles, and 1 cup of shredded cheese into the skillet. Stir well and taste, adjusting the seasoning with additional salt and pepper if needed.

Fill each roasted poblano pepper with the prepared mixture, dividing it evenly. Sprinkle the remaining shredded cheese on top.

Bake the stuffed peppers, uncovered, for 25 minutes. Remove from the oven and serve immediately. Garnish with fresh cilantro, if desired.