Preheat the oven to 450.
Heat a nonstick pan. Add cooking spray.
Add mushrooms and saute for 3-5 minutes or until browned.
Add remaining veggies.
Season with salt and pepper, and cook until tender.
Add flour and butter to the pan. Stir continuously until flour is golden, about 1 minute.
Add milk, demi-glace, sage, and 1-1.5c water to the pan.
Stir for 3-5 minutes, or until liquid has thickened.
Stir in shredded chicken and cook for another 2 minutes.
Remove from heat.
Put veggie/milk mixture into casserole dish.
If using box biscuit mix, prepare per box.
Top with small scoops of prepared biscuit mix or sliced canned biscuits, pending desired macros.
Bake uncovered for 12-14 minutes, or until biscuits are cooked and browned on the top.