Cook 1.5 lbs pasta in a large saucepan until al dente (see note 1). Once cooked, save about a cup of pasta water then drain. Set aside.
Using the same saucepan, stir 2 tbsp olive oil and 2 tbsp butter over medium heat until the butter has melted. Add onions and garlic and cook until onions are soft and translucent (2-3 minutes).
Pour 30 oz tomato sauce and add sugar, salt and pepper (see note 2). Lower the heat and cook for 30 minutes or until the sauce thickens considerably. Stir occasionally.
Remove from heat and add 1 cup heavy cream and 0.50 lbs shredded chicken. Stir to combine (see note 3). Taste and season once more if necessary. Serve with a generous helping of parmesan cheese and topped with fresh basil.
See post for tips on how to cook pasta.
I added 1 tsp each of sugar, salt and pepper. I suggest you start with 1/2 tsp then just adjust to taste.
If your sauce becomes too thick, you can add a little bit of pasta water at a time to thin it out to your desired consistency.