1. Cook the Rotini Pasta as follows: Cook the rotini according to the package directions. Allow to cool after draining.
2. Make the Salad Base: Combine the cooked pasta, chopped chicken, cherry tomatoes, red bell pepper, green onions, black olives, and shredded cheddar cheese in a large mixing bowl.

How to Make Spicy Ranch Dressing:

1. Whisk together 1 cup mayonnaise, 1/2 cup buttermilk, the entire package (1 oz) of ranch dressing mix, 1 teaspoon hot sauce (adjust to taste), 1/2 teaspoon garlic powder, and salt & pepper to taste in a medium-sized mixing bowl.
2. Until smooth, whisk:To ensure a smooth and well-mixed consistency, whisk the dressing until all of the ingredients are fully blended.
3. Consistency should be adjusted: If the dressing is too thick, add more buttermilk until it reaches the appropriate consistency. Whisk again to combine.
4. Adjust to taste: If required, taste the dressing and adjust the spices. Depending on your taste, you can add extra spicy sauce, garlic powder, or salt and pepper.
5. Chill: Combine and chill: In a large mixing bowl, drizzle the spicy ranch dressing over the spaghetti mixture. Toss everything until evenly coated. Enable the pasta salad to chill for at least 30 minutes before serving to enable the flavours to blend.
6. Chill before serving: Enjoy the delightful blend of spicy, creamy richness by serving the spicy ranch chicken pasta salad cold!