1. Preheat oven to 350°F.
2. Coat a large nonstick skillet with cooking spray; place over medium heat. Add onion, bell pepper, and garlic; sautee 3 to 5 minutes or until tender. Combine onion mixture, 2 tablespoons chili sauce, ½ cup cheese and remaining ingredients in a medium bowl.
3. Spoon meat mixture into 4 muffin cups coated with cooking spray. Top evenly with remaining cheese. Bake at 350°F for 12 minutes; top with remaining 2 tablespoons chili sauce. Bake an additional 10 minutes or until a thermometer registers 160°F. Let stand for 5 minutes before serving.
Don't be tempted to use a higher-fat ground beef. Using the leanest meat available helps ensure the right texture in this meatloaf since the juices don't drain away during cooking.