For a little extra spice, use a pure chili powder instead of a supermarket blend. Slideshow: More Mexican Recipes
In a large heavy skillet, heat the oil over medium high heat until hot, then stir in the on-ion, garlic, 1/2 teaspoon salt and 1/4 teaspoon pepper and cook, stirring occasionally, until golden, about 6 minutes. Stir in the chili powder and cook, stirring, until fragrant, about 1 minute. Stir in the tomatoes, chicken and kidney beans along with their juices, and cook until the chicken is cooked and the liquid is slightly thickened, about 10 minutes. Season the filling with salt and pepper to taste.
Preheat the oven to 350°F. Divide the filling between the tortillas. Roll each tortilla into a cylinder and place, side-by-side in a baking dish. Pour the remaining chili over the tortillas and sprinkle with the cheese.
Bake the enchiladas until the filling is hot and the cheese is melted, about 15 minutes. Serve.