Cook rigatoni to desired doneness as directed on package. Drain; cover to keep warm.
Meanwhile, spray large nonstick skillet with nonstick cooking spray. Heat over medium-high heat until hot. Add onion and bell pepper; cook and stir 5 to 6 minutes or until crisp-tender.
Add bratwurst and marinara sauce; mix well. Reduce heat to medium-low; cook 5 to 10 minutes or until thoroughly heated, stirring occasionally.
Stir in cooked rigatoni. Sprinkle with cheese.