Preheat your oven to 375°F. Lightly coat a 9×13-inch metal or glass baking dish with non-stick cooking spray and set it aside.

In a medium mixing bowl, combine the condensed cream of chicken soup, sour cream, milk, ½ teaspoon of the garlic powder, the onion powder, paprika, salt, and ground black pepper. Whisk vigorously until the wet base is smooth and entirely even in consistency.

In a separate large mixing bowl, combine the shredded rotisserie chicken, thawed and drained hash browns, 1 cup of the shredded sharp cheddar cheese, the mozzarella cheese, and the sliced green onions. Use a silicone spatula to gently toss the ingredients together.

Pour the whisked soup mixture directly over the chicken and potato bowl. Fold firmly from the bottom up until the potatoes and meat are completely coated in the cream baseline.

Transfer the mixture into your prepared baking dish, using a spatula to spread it out into a flat, level, and uniform layer. Scatter the remaining 1 cup of shredded cheddar cheese evenly over the top of the potato layer.

In a small bowl, combine the finely crushed Ritz cracker crumbs, melted unsalted butter, the remaining ½ teaspoon of garlic powder, and the chopped fresh parsley. Stir with a fork until the crumbs are evenly moistened and resemble wet sand.

Sprinkle the buttery cracker mixture uniformly over the top of the cheese layer across the entire surface of the casserole.

Place the dish uncovered onto the middle oven rack and bake at 375°F for 40 to 45 minutes. Watch for the edges to bubble aggressively and the cracker topping to take on a deep, beautiful golden-brown color.

Remove the casserole from the oven and let it rest on a wire cooling rack for 10 minutes before serving. This cooling window allows the internal melted cheeses and starches to set, ensuring clean, scoopable portions that hold their shape on the plate. Serve warm.