Preheat the oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with nonstick spray or a teaspoon of olive oil.
Prep the chicken. If using rotisserie or leftover chicken, shred or chop into bite-size pieces.
If starting with raw chicken, cook it first (poach, grill, or pan-sear), then shred.
Mix the protein base. In a large bowl, whisk together Greek yogurt, cottage cheese, and eggs until smooth. Stir in buffalo sauce, garlic powder, onion powder, smoked paprika, pepper, and salt.
Taste and adjust buffalo sauce if you want more heat.
Add the chicken and veggies. Fold in the chicken, chosen vegetables, and half of the mozzarella. The mixture should be thick but spreadable.
Assemble the bake.
Spread the mixture evenly in the prepared baking dish. Top with the remaining mozzarella and the blue cheese, if using.
Bake for 25–30 minutes, until the edges are bubbling and the center is set. The top should be lightly golden and the cheese melted.
Rest and garnish.
Let it sit for 5–10 minutes to firm up. Sprinkle with sliced green onions. For extra zing, drizzle a little more buffalo sauce over the top.
Serve with crunchy celery sticks, a side salad, or roasted potatoes.
Ranch or blue cheese dressing on the side is a welcome touch.