Cook noodles according to package directions. Drain; keep warm. In a small bowl stir together sour cream and flour; set aside.
Meanwhile, in a large skillet heat oil over medium-high heat. Add turkey. Cook and stir for 4 to 5 minutes or until browned and no longer pink inside. Remove from skillet.
Add mushrooms to skillet. Cook and stir for 3 minutes. Add broccoli. Cook and stir for 2 minutes more or until mushrooms are browned and tender and broccoli is crisp-tender.
Add broth, onion powder, and pepper to skillet. Bring to boiling. Whisk in sour cream mixture. Cook and stir until thickened
and bubbly. Cook and stir 1 minute more. Stir turkey into mixture in skillet; heat through.
Serve turkey mixture with noodles.