In the sleeve of a slow cooker, add the onions, peppers, corn, tomatoes, garlic, 1 tablespoon chile powder, chipotle, and broth. Season with and salt and pepper, to taste. Cook on low for 4 to 6 hours.
In a deep skillet over medium heat, add the canola oil and heat to 365 degrees F. Fry the tortilla pieces until brown and crispy, 1 to 2 minutes. Drain on brown paper and immediately season with salt and the remaining 1 tablespoon chile powder. (Reserve half the chips for Online Round 2 Recipe Creamy Mexican Dip with Spiced Chips.)
Preheat the broiler.
(Reserve 1 cup of the onion and pepper mixture for Round 2 Recipe Creamy Mexican Dip with Spiced Chips.) Ladle the soup into ovenproof bowls or crocks and top each with 2 tablespoons cheese. (Reserve remaining 1/2 cup cheese for Round 2 Recipe Crispy Steak Sandwiches.) Put the bowls on a sheet pan and put under the broiler until the cheese is brown and bubbly, 1 to 2 minutes. Garnish with scallions and serve.