Preheat your oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish.

Cook the fettuccine pasta according to package directions until al dente, then drain well.

In a large mixing bowl, combine the softened cream cheese, sour cream, cottage cheese, melted butter, and garlic powder. Mix until smooth and well blended.

Fold the shredded cooked chicken and cooked fettuccine pasta directly into the creamy cheese mixture until everything is evenly coated.

Transfer the mixture into your prepared baking dish and spread it out evenly. Top generously with the shredded cheddar cheese and sprinkle the panko breadcrumbs evenly over the top.

Bake in the preheated oven for 25 minutes, or until the cheese is completely melted, bubbling around the edges, and the panko topping is golden brown.

Remove from the oven, garnish with freshly chopped green onions, let it cool for 5 minutes, and serve warm!