Preheat oven to 375° F. Prepare a baking sheet with parchment paper or cooking spray.
Mix cumin, chili powder, garlic powder and salt. Coat chicken breast with 1 tablespoon of olive oil. Sprinkle chicken breast with 1-2 teaspoons of spice mix. Place chicken on prepared baking sheet and bake until cooked all the way through, 15-20 minutes. Remove from oven and cut into cubes. Set aside.
In a large Dutch oven, over medium-high heat, add 1 tablespoon olive oil, onion, green and red pepper and cook until onions soften and begin to color, about 5 minutes. Add remaining spice mix and stir to combine.
Add garlic and cook for about 30 seconds more, then add Rotel tomatoes, cubed chicken (along with any accumulated juices), chicken broth, hot water and tomato paste.
Stir to combine and bring mixture to a boil. Reduce heat to low and simmer for about 20 minutes. Add black beans and corn.
Mix the cornmeal with ½ cup water and add the mixture to the pot while stirring and continue to simmer the soup for another 10-15 minutes, stirring occasionally. Adjust salt and seasoning to taste.
Cut the tortillas into 2-3 inch uniform strips. Add most of them into the soup just before serving. Top individual bowls with remaining tortilla strips.