Cook fettuccine in large pot with tablespoon salt to 1 minute short of package time. Reserve 1 cup pasta water; drain.
Meanwhile, toss chicken with paprika, garlic powder, onion powder, thyme, cayenne, chicken salt, and pepper. Heat oil in large skillet; cook strips 6 to 8 minutes until browned and at least 165°F. Plate.
Soften bell pepper and onion 5 to 6 minutes. Add broth; scrape browned bits. Add cream; simmer 3 minutes.
Return chicken with pasta and 1/4 cup reserved water; toss over medium-low 1 to 2 minutes until tender and coated.
Add lemon juice off heat; loosen with pasta water if needed. Serve with peppers distributed through noodles.