Start by cooking the chicken breasts in a large saucepan with diced onions, tomatoes, chicken broth, and garlic powder. Simmer for 30 minutes until the chicken is tender enough to shred. Allow it to cool slightly before shredding, then discard the cooking liquid. The blend of broth and aromatics infuses the chicken with incredible flavor.
Heat vegetable oil over medium heat in a saucepan and whisk in the flour to make a roux. Cook until it begins to bubble, then stir in the chili powder, cumin, onion powder, garlic powder, salt, and cayenne pepper. Whisk in the chicken broth slowly and simmer for about 10 minutes until thickened. Think of it as creating a Mexican-inspired gravy.
Spread a thin layer of enchilada sauce at the bottom of your baking pan. Spoon some sauce into the center of each tortilla, add shredded chicken and a sprinkle of both cheeses, then roll tightly. Arrange them seam-side down in the baking pan.
Pour the remaining enchilada sauce over the rolled tortillas, ensuring they’re evenly coated. Top generously with the grated Monterey Jack and Cheddar cheese blend.
Bake the enchiladas in a 400°F oven for about 20 minutes or until the cheese is bubbly and golden. Once out of the oven, allow them to cool slightly, and they’re ready to serve.