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

In a large mixing bowl, combine the condensed cream of chicken soup, sour cream, chicken broth, garlic powder, onion powder, dried thyme, salt, and black pepper. Whisk the ingredients firmly together until they emulsify into a perfectly smooth, rich gravy baseline.

Add the shredded cooked chicken and frozen mixed vegetables directly into the bowl with the gravy baseline. Stir with a large rubber spatula to coat the mix-ins uniformly.

Pop open the can of refrigerated biscuits. Separate the individual biscuits and use a sharp knife or kitchen shears to cut each biscuit into 4 to 6 equal bite-sized pieces.

Drop the biscuit pieces directly into the chicken filling bowl, along with ½ cup of the shredded cheddar cheese. Toss the mixture gently with your spatula to coat the dough pieces without smashing them.

Pour the entire combined mixture straight into the prepared baking dish. Use the spatula to spread it into a level layer, ensuring the biscuit dough pieces are scattered evenly across the pan rather than clumped together.

Place the dish uncovered on the middle oven rack and bake at 375°F for 25 to 30 minutes. The casserole is ready for its final step when the biscuits look puffed up and lightly colored.

Remove the dish briefly and scatter the remaining ½ cup of cheddar cheese across the surface. Return the casserole to the oven for an additional 5 minutes, or until the cheese matrix is entirely melted, bubbly, and golden brown.

Remove from the oven and let it stand flat on a cooling rack for 5 to 10 minutes. This cooling window allows the hot gravy baseline to thicken up slightly before scooping. Serve hot.