Heat the olive oil in a large skillet over medium heat and sauté the garlic cloves until fragrant.
Dice the chicken breasts and add them to the skillet along with the pepper and Italian seasoning.
Cook the chicken until it is no longer pink, stirring occasionally.
In a bowl, whisk together the onion soup mix, cream of mushroom soup, milk, and water until smooth.
Pour the creamy mixture into the skillet with the chicken.
Stir in the Parmesan cheese and bring the mixture to a gentle boil.
Reduce the heat to low and simmer for 15 minutes, stirring occasionally.
Meanwhile, cook the fettuccine in a large pot of salted boiling water according to package directions until al dente.
Drain the pasta and toss it with the creamy chicken sauce until well coated.
Serve immediately.