Preheat oven to 350 degrees F. and spray a 9x13 pan with cooking spray.
In a large bowl, whisk together Greek yogurt, almond milk, garlic powder, onion powder, salt, and pepper until smooth.
Stir in the chicken, broccoli, green onions, half of the cheddar cheese, and half of the bacon. Mix well.
Spread the mixture evenly in the prepared baking dish.
Top with the remaining cheese and bacon.
Bake for 25-30 minutes, or until the casserole is hot, bubbly, and golden on top.
Let rest for 5 minutes before serving. Garnish with extra green onions if desired.