Preheat the oven: Set your oven to 400°F (200°C). Lightly oil a 9x13-inch baking dish or line it with parchment for easy cleanup.
Prep the chicken: Pat the chicken dry with paper towels.
If the breasts are very thick, slice them horizontally to create even cutlets about 3/4-inch thick. Even thickness ensures juicy, evenly cooked chicken.
Make the ranch mixture: In a bowl, mix Greek yogurt, ranch seasoning, garlic powder, onion powder, smoked paprika, salt, and pepper until smooth.
Coat the chicken: Add the chicken to the bowl and toss to coat evenly. You want a generous, creamy layer on each piece.
Add optional veggies: If using vegetables, toss them with a little olive oil, salt, and pepper. Scatter them in the baking dish, then place the coated chicken on top.
Top with cheese: Sprinkle mozzarella and Parmesan evenly over the chicken.
Bake: Bake for 18–25 minutes, depending on thickness, until the chicken reaches an internal temperature of 165°F (74°C).
The top should be lightly golden and bubbly.
Rest and garnish: Let the chicken rest for 5 minutes. Sprinkle with fresh parsley or chives. Serve with lemon wedges if you like a bright finish.
Serve: Pair with roasted potatoes, brown rice, cauliflower rice, or a crisp salad.
Spoon any pan juices over the chicken for extra flavor.