Preheat your oven to 350°F and give the bottom and sides of a casserole dish a generous spritz of cooking spray.

In a skillet, melt the butter and sauté the onions and red bell peppers until they're nice and tender.

In a medium-sized bowl, mix together the sautéed veggies, cooked chicken, cream of chicken soup, frozen vegetables, mayo, and milk until everything's combined and looking delish.

Spoon the mixture into the prepared casserole dish and pop it in the oven for 15 minutes.

After 15 minutes, take the casserole out and sprinkle half of the cheddar cheese on top of the chicken mixture.

Now it's time for the biscuits! Arrange them on top of the cheese layer.

Sprinkle the remaining cheddar cheese over the biscuits, and bake for another 20 minutes, or until the cheese is all melty and the biscuits are golden brown and cooked through. Enjoy your masterpiece!