Preheat your oven to 350°F (175°C) and lightly oil a large baking sheet.

Place the poblano pepper halves on the baking sheet, cut side up, ensuring they don't overlap.

Bake the peppers for 10-15 minutes to soften slightly.

While peppers are baking, heat a large skillet over medium heat.

Add the ground beef to the skillet and sprinkle with cumin, chili powder, and garlic powder.

Cook the beef, stirring occasionally, until browned and fully cooked, about 5-8 minutes.

Mix in the cooked rice, black beans, corn, diced tomatoes, and green chiles into the skillet with the beef.

Cook the mixture for an additional 1-2 minutes, then remove from heat.

Spoon the beef and rice mixture evenly into the baked poblano pepper halves.

Top each stuffed pepper with a generous sprinkle of Mexican-blend cheese.

Return the stuffed peppers to the oven and bake for another 10 minutes, or until the cheese is melted and bubbly.

Let the peppers cool for a few minutes before serving.