Baked Beef Chiles Rellenos Casserole

Name: Baked Beef Chiles Rellenos Casserole
Ingredients: 6 large poblano peppers, halved and seeded; 1.5 pounds ground beef, or to taste; 1 tablespoon chili powder; 2 cloves garlic, minced; 1 teaspoon ground cumin; 1 teaspoon dried oregano; 0.25 teaspoon ground cayenne pepper; 0.25 teaspoon ground paprika; 0.25 teaspoon ground dried chipotle pepper; salt and ground black pepper to taste; 1 large onion, chopped; 2 (14.5 ounce) cans diced tomatoes with green chile peppers; cooking spray; 3 cups shredded Mexican cheese blend, or to taste