Cook fettuccine pasta according to package directions. Drain, reserving about 1/2 cup of pasta water.
In a large skillet, melt butter over medium heat. Add minced garlic and cook until fragrant, about 1 minute.
Add heavy cream and buffalo sauce to the skillet. Stir well and bring to a simmer.
Stir in grated Parmesan cheese until the sauce is smooth and creamy. Season with salt and pepper.
Add the cooked shredded chicken to the sauce and stir to combine. Let it simmer for a few minutes to heat through.
Add the drained fettuccine to the skillet with the sauce. Toss to coat the pasta evenly. If the sauce is too thick, add a little of the reserved pasta water until desired consistency is reached.
Serve immediately, garnished with chopped fresh parsley.
Notes
Adjust the amount of buffalo sauce to your preferred level of spiciness.