Preheat oven to 400°F (200°C). Grease a 9-inch pie dish or small baking dish.

Stir chicken, vegetables, soup, milk, thyme, salt, and pepper in a bowl until combined. Spread into prepared dish.

Arrange biscuits on top; brush with melted butter. Cut a few small slits in biscuits to vent.

Bake 18–22 minutes until biscuits are golden and filling bubbles. Let sit 5 minutes before serving.