01 -
Preheat the oven to 375°F and lightly grease a 9 x 9-inch baking dish.
02 -
In a large skillet over medium heat, cook bacon until crispy, about 7 minutes. Transfer to paper towels to drain excess grease.
03 -
In a gallon-sized resealable plastic bag, combine olive oil, diced chicken, and dry Ranch dressing mix. Seal and shake to coat chicken evenly.
04 -
Add coated chicken to the skillet and cook until fully browned and no longer pink inside, stirring occasionally.
05 -
Boil pasta shells in salted water until al dente, then drain and transfer to the prepared baking dish.
06 -
Layer cooked chicken and Alfredo sauce over the pasta in the baking dish. Sprinkle shredded mozzarella and cheddar cheeses on top, then evenly distribute the cooked bacon. Season with salt and pepper to taste.
07 -
Place the baking dish in the preheated oven and bake until the casserole is bubbly and the cheese has melted, approximately 15 minutes.
08 -
Remove from oven and serve immediately.