Preheat oven to 375 degrees and spray a 2 quart casserole dish (or similar size) with cooking oil. Set aside.
Heat a large non-stick skillet over medium-high heat. When the skillet is hot add in the broccoli florets and sauté for 1 minute. Add in 1/4 cup of water and cover with a lid. Let the broccoli steam for approximately 3 minutes then remove it from the skillet onto a plate.
Return the skillet to the stove and spray with cooking oil. Add in the onion and garlic and sauté for 2 minutes. Add in the chicken and season with salt and pepper. Sauté the chicken until it is cooked through then remove the mixture from the skillet and onto the plate with the broccoli.
Lower the heat to medium and melt the butter in the skillet. Whisk in the flour, let it cook for 1 minute. Slowly whisk in the milk until the flour mixture is dissolved and the sauce starts to thicken. Season with salt and pepper and continue to whisk until the sauce is thick enough to coat the back of a spoon.
Add in the cheese, reserving 1/4 cup and whisk until melted and smooth. Remove the skillet from the heat and whisk in the Greek yogurt. Add the chicken, broccoli and wild rice to the sauce and stir together until everything is combined.
Pour into the prepared casserole dish and top with the remaining shredded cheese. Cover loosely with foil and bake for approximately 20-30 minutes or until bubbly and the cheese is melted.
*Nutritional information is an estimate. Please consult a doctor or nutritionist for the most accurate nutritional info.