Render the bacon over low heat in a large skillet until crisp; this ensures maximum flavor. Transfer the cooked bacon to a paper towel-lined plate and reserve the drippings separately. Once cooled, coarsely chop the bacon.

Slice the chicken breasts horizontally into 2–3 thinner portions. Pat dry, then season both sides lightly with salt, pepper, onion powder, and Italian seasoning. Heat two tablespoons of bacon drippings or oil over medium-high heat and sear the chicken for 3–4 minutes per side until a golden crust forms. Remove to rest before cutting into bite-sized cubes.

Meanwhile, bring a pot of salted water to a boil and cook the rotini until al dente. Drain and set aside.

In the same skillet, melt butter over medium heat. Sauté the garlic briefly for one minute, then whisk in the flour and stir continuously for another minute. Warm the half and half in the microwave for 40 seconds to temper, then gradually incorporate it into the skillet, stirring to combine. Allow the mixture to gently bubble, then reduce the heat.

Stir in the ranch seasoning followed by the shredded cheddar cheese, ensuring a smooth consistency as it thickens.

Fold the cooked pasta into the creamy sauce, then add the chicken. Let everything warm through thoroughly. Stir in the chopped bacon or reserve it as a garnish before serving.