Cook pasta: Boil the pasta according to package instructions until al dente. Drain and set aside.
Prepare chicken: If not already cooked, cook chicken in a skillet or bake until no longer pink, then dice or shred.
Cook bacon: Cook the bacon until crispy, then crumble it into pieces.
Mix the sauce: In a large bowl, combine the ranch dressing, sour cream, garlic powder, onion powder, salt, and pepper.
Combine everything: In the bowl with the sauce, add the cooked pasta, chicken, bacon, and vegetables (if using). Stir to coat everything evenly with the sauce.
Assemble the casserole: Pour the mixture into a greased 9×13 baking dish. Sprinkle the cheddar and mozzarella cheeses evenly on top.
Bake: Place the dish in the preheated oven and bake for 20–25 minutes, or until the cheese is bubbly and golden.
Serve: Let the casserole cool slightly before serving.
Tips:
Add more veggies like spinach or bell peppers for a healthier version.
You can swap sour cream for Greek yogurt for a tangy, lighter option.