Bring 6 cups of water to a boil in a large pot. Add the 2 cups of dried pasta and cook until tender, about 10–12 minutes, according to package directions.
Drain the pasta in a colander and immediately transfer to a large bowl. Drizzle 1/2 tablespoon olive oil over the pasta and toss to prevent sticking.
Let the pasta cool at room temperature until warm, then refrigerate until fully chilled, about 20 minutes or until cold.
When the pasta is cold, add the cubed rotisserie chicken, 1 cup Greek yogurt, 1/2 cup mayonnaise, chopped green onions, 2 tablespoons ranch dry mix, 1 teaspoon dried parsley (or 2 Tbsp fresh), 1 cup shredded Colby Jack, 1 cup peas, 1/4 teaspoon salt, and 1/4–1/2 teaspoon black pepper to the bowl.
Mix everything thoroughly until evenly coated. Taste and adjust seasoning or mayo if desired.
Cover and chill the pasta salad in the refrigerator until very cold before serving.