Preheat your oven to 350°F (175°C). Spray a 9x13-inch baking dish with cooking spray.

Pat the chicken dry, season with salt, pepper, and paprika. Heat olive oil in a skillet over medium heat and sear chicken for 5-7 minutes. Remove chicken and set aside.

Sauté diced onion, carrots, and celery in the same skillet for 5 minutes. Add minced garlic and cook for an additional minute.

Sauté sliced baby bella mushrooms in more olive oil for 5-8 minutes until golden brown. Combine with chicken and vegetables.

In a small bowl, whisk chicken broth and cornstarch. Melt butter and add flour in the skillet to create a roux. Slowly add broth mixture and milk until the sauce thickens.

Stir in sharp cheddar and Parmesan until melted. Combine this sauce with chicken, vegetables, and cooked wild rice.

Transfer the mixture to the prepared baking dish, top with remaining cheese, and mix panko breadcrumbs with melted butter to sprinkle on top.

Bake in the preheated oven for 30-35 minutes until hot and bubbly with a golden top.