Heat oil in a large skillet over medium heat. Add chicken, onion and garlic; saute until chicken is mostly cooked through, about 10 minutes. Stir in the crushed tomatoes, mushrooms and Italian seasoning. Cook for about 5 minutes, stirring frequently.
Reduce heat and stir in the sugar. Simmer for at least 15 minutes. Meanwhile, bring a large pot of lightly salted water to a boil; add rotini pasta and cook until al dente. Drain and serve topped with the chicken mixture and grated Parmesan cheese.
