Cook spaghetti in Dutch oven or large saucepan to desired doneness as directed on package. Drain; return to Dutch oven. Cover to keep warm.
Meanwhile, in large nonstick skillet over medium heat, cook sausage, fennel and garlic until sausage is no longer pink; drain and remove from skillet.
Add sugar snap peas, mushrooms and broth to skillet; heat until bubbly. Simmer 3 to 4 minutes, stirring frequently. Stir in tomatoes and onions; cook and stir over medium heat for 2 minutes. Add sausage mixture and parsley; cook an additional 1 minute or until hot. Add to cooked spaghetti; toss gently until well mixed.