Take a large pot of water, about halfway full. Add some salt to the water, about 1 tbsp, or to taste. Then add in your fettuccine noodles and cook for approximately 4 minutes (or per package directions).
When you drain out the water from the pasta pot, make sure to reserve a cup of the pasta water. Rinse the noodles with cold water to stop them from cooking.
Preheat your oven to 350. Grab a cast iron or an oven proof pan. Season the chicken and heat up the cast iron. Saute your chicken for a few minutes on each side and then place in the heated oven. Cook for 10 minutes.
While the chicken is cooking. you can start by making your cheese sauce in a separate pan on medium heat.
Melt the butter and add the flour. Stir until combined. Slowly stir in half of the milk. Add the cheese and stir to combine. Keep adding the rest of the milk until you get the thickness you want. Chop up the chicken and add it to the sauce mix.
Next, add in your drained fettuccine noodles to a large mixing bowl or a pasta serving dish. Use the reserved pasta water to thin if necessary.
Poor to cheese mix over the noodles and stir to combine.
Now you can serve yourself a plate and enjoy! Just make sure you mix up all the ingredients before digging in.