Preheat your oven to 350°F. While it heats, soften the cream cheese to room temperature (about 70°F) if it hasn't been already—this ensures it blends smoothly into the mixture without lumps. Measure out all your ingredients and have them ready: shredded chicken, cooked rice, soup, seasonings, cheese, panko, and melted butter. This organized approach prevents scrambling mid-assembly.

Cook the rice according to package directions. Once cooked, set it aside to cool slightly so it won't break apart when mixed with the other ingredients. The rice should be fluffy and separate, not mushy, as it will continue cooking in the oven.

In a large mixing bowl, combine the shredded chicken, cooked rice from Step 2, cream of chicken soup, softened cream cheese, Italian dressing mix, garlic powder, onion powder, pepper, and chicken stock. Mix thoroughly until the cream cheese is fully incorporated and the mixture is evenly combined—I like to use a sturdy wooden spoon and take my time here to avoid streaks of cream cheese. Once smooth, stir in 1.5 cups of colby jack cheese until everything is well distributed.

Spread the mixture from Step 3 evenly into a greased 9x13-inch baking dish. In a small bowl, combine the panko breadcrumbs with the melted and slightly cooled butter, stirring until the crumbs are evenly moistened and crumbly. Sprinkle the remaining 0.5 cup colby jack cheese over the casserole base, then top with the buttered panko mixture, distributing it in an even layer. For extra crunch, I prefer spreading the panko topping in clusters rather than completely even—this gives you some pockets of crispy texture throughout.

Bake the casserole in the preheated 350°F oven for 25-30 minutes, until the top is golden brown and the mixture is hot throughout. The panko should be crispy and lightly golden, and you should see the edges bubbling slightly around the sides of the dish. Remove from the oven and let rest for 3-5 minutes before serving—this allows the casserole to set up slightly, making it easier to portion.