Bring a large pot of salted water to a boil. Add the fettuccine and cook 8–10 minutes until al dente, stirring occasionally. Drain and set aside.
While the pasta cooks, melt 2 tablespoons unsalted butter in a large saucepan over medium-high heat. Season the chicken pieces with 1/2 teaspoon salt and 1/2 teaspoon pepper.
Add the chicken to the pan and cook, stirring occasionally, until golden and cooked through, about 8 minutes. Remove the chicken to a plate and set aside.
In the same saucepan, melt the remaining 8 tablespoons butter over medium-high heat. Add the ricotta, heavy cream, and grated Parmesan and stir to combine.
Bring the sauce to a gentle boil, then reduce heat to medium-low and simmer about 5 minutes, stirring occasionally, until smooth and slightly thickened. Taste and adjust salt and pepper if needed.
Return the cooked chicken to the sauce, add the drained fettuccine, and toss until the pasta and chicken are coated and heated through.
Serve immediately garnished with extra Parmesan and chopped parsley.