Cook fettuccine in a large pot of water with the tablespoon salt until 1 minute short of the package time. Reserve 1 cup pasta water before draining.
Meanwhile, toss chicken with paprika, garlic powder, onion powder, thyme, cayenne, chicken salt and pepper. Heat oil in a large skillet and cook strips for 6 to 8 minutes until browned and at least 165°F; transfer to a plate.
Cook bell pepper and onion in the skillet for 5 to 6 minutes until softened. Pour in broth and scrape up the browned bits, then stir in cream and simmer for 3 minutes.
Return chicken and add fettuccine with 1/4 cup reserved pasta water. Toss over medium-low heat for 1 to 2 minutes until the noodles are tender and evenly coated.
Stir in lemon juice off the heat, loosen with more pasta water if needed and serve with the peppers distributed through the noodles.