Melt butter in saucepan over medium heat. Stir in garlic & onion. Cook 2 mins.n Pour in the can of tomatoes w/ juice and sugar. Increase heat to med-high. Bring to a simmer, stirring for 10 mins.
Stir in cream, season w/ salt & pepper. Simmer 3 min. Lower heat to keep warm. In shallow bowl, combine breadcrumbs, 2 tbsp parmesan cheese, and oregano. In another shallow bowl, whisk together egg and milk.
Dip each chicken breast into egg mix, then press into bread crumb mix. Make sure to coat both sides. Heat oil in lg skillet over medium heat. Add chicken and cook, turning once for about 10 mins, or until browned on both sides. Spoon sauce over chicken, top w/ mozzarella cheese and parmesan cheese. Let stand so sauce melts the cheeses and serve over pasta.