Heat Olive oil in a large skillet over medium-high heat. Add Chicken and cook until browned and cooked through, about 8-10 minutes. Remove from skillet and set aside. Slice or cube the Chicken.
Cook Pasta according to package directions. Reserve 1 cup of pasta water before draining.
In the same skillet, melt Butter over medium heat. Add Garlic and cook for 1 minute until fragrant.
Pour in Heavy cream and bring to a simmer. Reduce heat to low and stir in Parmesan cheese and Cayenne pepper until melted and smooth.
Season Sauce with Salt and Pepper.
Add cooked Pasta and Chicken to the Sauce. Toss to coat, adding reserved pasta water as needed to reach desired consistency.
Garnish with Chopped green onions and serve immediately.
