Cook the pasta according to package instructions until it's al dente. Drain and set aside.
Melt the butter in a large skillet over medium-high heat.
Add the chicken to the skillet, then sprinkle with chili powder, red chili flakes, salt and pepper. Cook until the chicken is no longer pink, about 5 minutes.
Add the tomatoes, green onions and parsley. Stir and cook for another 2 minutes.
Add the heavy cream and chicken broth, and cook until it comes to a boil.
Add the cooked rotini pasta and stir everything together.
Sprinkle with mozzarella cheese and additional parsley if preferred. Serve warm.