Cut tomatoes in half crosswise and scoop out centers; chop and reserve scooped out pieces. Drain hollowed tomatoes upside down on paper towel.
Heat olive oil in large skillet over medium heat and cook onion and bacon, stirring occasionally, 5 minutes until onion is transparent and bacon is crisp. Stir in chicken and cook 2 minutes. Remove skillet from heat and stir in Parmesan cheese, basil, parsley and reserved tomato pulp. Stir in 250 mL prepared Knorr® Alfredo Pasta Sauce Mix.
Arrange tomatoes, cut-side-up, on baking sheet. Evenly fill tomatos with chicken filling, mounding slightly, then sprinkle with mozzarella cheese. Bake 15 minutes or until filling is bubbling and cheese is starting to turn golden brown.