Step 1: Prepare the Seasoned Chicken Filling
Preheat your oven to 375°F (190°C). In a large mixing bowl, combine the shredded chicken, taco seasoning, and ½ cup of water. Toss until the chicken is evenly coated. Add the rinsed black beans, drained corn, and the entire can of undrained diced tomatoes with green chiles. Stir gently to combine. This is your flavorful, colorful filling base.

Step 2: Create the Creamy, Zesty Binder
In a separate medium bowl, combine the softened cream cheese and sour cream. Use a hand mixer or a sturdy whisk to beat them together until completely smooth and lump-free. This step is crucial. Then, whisk in the chunky salsa, chicken broth, cumin, and garlic powder until you have a smooth, pourable cream sauce.

Step 3: Assemble the First Layer
Lightly spray a 9×13 inch baking dish with non-stick cooking spray. Spread half of the crushed tortilla chips in an even layer on the bottom of the dish. This creates a foundational crunch.

Step 4: Add the Hearty Filling
Spoon all of the chicken and bean mixture evenly over the tortilla chip layer. Press down gently to create a solid, even layer.

Step 5: The Creamy Sauce Layer
Pour the entire creamy salsa sauce mixture over the chicken layer. Use a spatula to spread it evenly, ensuring it reaches all the way to the edges of the dish. This sauce will seep down and bind everything together as it bakes.

Step 6: The Cheesy, Crunchy Finale
Sprinkle 2 cups of the shredded Mexican cheese evenly over the creamy sauce. Top with the remaining half of the crushed tortilla chips. Finally, sprinkle the remaining 1 cup of cheese over the top of the chips.

Step 7: Bake to Bubbly, Golden Perfection
Cover the baking dish loosely with aluminum foil. Bake for 20 minutes. Then, carefully remove the foil and bake for an additional 10-15 minutes, or until the cheese is completely melted, bubbly, and the edges are lightly golden brown. The chips on top should be toasty.

Step 8: Rest, Garnish, and Serve Fiesta-Style
Remove the casserole from the oven and let it rest for 10 minutes. This is essential for the layers to set, making it easier to cut and serve. Present the casserole at the table alongside a vibrant array of all your fresh garnishes in small bowls. Allow everyone to top their portion with their favorite fixings—shredded lettuce, fresh tomatoes, jalapeños, a dollop of sour cream, and a squeeze of lime