Cook Sausage:
Heat olive oil in a large skillet over medium heat. Add sausage and cook, breaking up with a spoon, until browned and cooked through, about 6-8 minutes. Remove sausage and set aside.

Sauté Aromatics:
In the same skillet, add diced onion and garlic. Cook until softened, about 3-4 minutes.

Add Liquids and Pasta:
Return sausage to the skillet. Stir in buffalo sauce, chicken broth, and heavy cream. Bring to a simmer.

Cook Pasta:
Add uncooked pasta to the skillet. Stir to combine and ensure pasta is submerged in the liquid. Cover and cook over medium-low heat, stirring occasionally, until pasta is tender and most of the liquid is absorbed, about 12-15 minutes.

Add Cheese:
Stir in shredded mozzarella cheese until melted and creamy. Season with salt and pepper to taste.

Serve:
Garnish with chopped green onions if desired. Serve hot.