Prepare the Chicken and Vegetables: First, dice your chicken breast or thighs into bite-sized pieces. Finely chop the onion and mince the garlic.

Brown the Chicken: Heat olive oil in your large skillet or Dutch oven over medium-high heat. Add the diced chicken and cook until lightly browned on all sides, about 5-7 minutes. Remove the chicken from the skillet and set aside.

Sauté Aromatics: In the same skillet, add the chopped onion. Cook for 3-5 minutes until softened. Add the minced garlic and cook for another minute until fragrant.

Create the Creamy Sauce: Pour in the chicken broth, cream of chicken soup, and milk. Whisk until smooth, then bring to a gentle simmer. Add thyme, black pepper, and salt.

Combine and Simmer: Stir the cooked chicken back into the sauce and add the frozen mixed vegetables. Let it simmer for 2-3 minutes.

Prepare the Biscuits: Cut each refrigerated biscuit into quarters.

Assemble the Casserole: Pour the mixture into your baking dish and arrange the biscuit pieces over the top.

Add Cheese: Sprinkle the shredded cheddar cheese evenly over the biscuits.

Bake to Golden Perfection: Preheat your oven to 375°F (190°C) and bake for 25-30 minutes.

Rest and Serve: Let the casserole rest for 5-10 minutes before serving.