Preheat and prep. Heat the oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with oil spray.
If using raw chicken, season with salt and pepper, then cook and shred or dice.
Cook the turkey bacon. Crisp it in a skillet until browned. Drain on paper towels and crumble. Set aside.
Make the creamy base. In a large bowl, whisk Greek yogurt, reduced-fat cream cheese, ranch seasoning, chicken broth, garlic, onion powder, and smoked paprika until smooth.
Taste and season with salt and pepper. It should be boldly seasoned.
Add the mix-ins. Stir in shredded chicken, riced cauliflower (thawed and squeezed dry), peas and carrots, and half the green onions. Fold in 2/3 of the shredded cheddar.
Assemble the casserole. Spread the mixture evenly in the baking dish.
Top with remaining cheddar and the crumbled turkey bacon. If using panko, toss it with a light spritz of oil and sprinkle over the top for extra crunch.
Bake. Bake uncovered for 20–25 minutes, or until hot and bubbling at the edges. If you want a deeper golden top, broil for 1–2 minutes at the end, watching closely.
Finish and serve. Let it rest 5–10 minutes to set.
Sprinkle with remaining green onions. Serve with a side salad or steamed greens.