Season the chicken pieces generously with salt and pepper. Heat olive oil in a large skillet over medium-high heat. Add chicken and cook for 5-7 minutes, stirring occasionally, until golden brown and cooked through. Remove chicken from the skillet and set aside.

While the chicken cooks, bring a large pot of salted water to a rolling boil. Add the fettuccine and cook according to package directions until al dente, usually 8-10 minutes. Reserve 1 cup of the pasta cooking water before draining the pasta.

In the same skillet (no need to clean it!), melt butter over medium heat. Add minced garlic and cook for 1 minute until fragrant, being careful not to burn it.

Pour in the heavy cream and chicken broth. Bring the mixture to a gentle simmer, then reduce heat to low and let it cook for 2-3 minutes, stirring occasionally, until it thickens slightly.

Stir in the fresh lemon juice, chopped parsley, chopped dill, and grated Parmesan cheese. Whisk until well combined and the cheese has melted into the sauce. Season with salt and pepper to taste.

Add the cooked chicken and drained pasta to the skillet with the sauce. Toss gently to coat everything evenly. If the sauce seems too thick, add a splash or two of the reserved pasta water until it reaches your desired consistency.

Divide the pasta among serving bowls and garnish with extra grated Parmesan cheese and fresh herbs, if desired. Enjoy warm!