Preheat oven to 350 degrees.
Heat butter and oil in a large skillet over medium heat. Add bell pepper, onion, and tomatoes and cook until tender.
Add garlic, salt and pepper and cook for 1 minute.
Add flour and stir to combine for 1 minute to cook the raw flour taste out.
Add chicken broth and bring to a boil while stirring. Once it comes to a boil, turn off heat and stir in heavy cream. (It will be a thin sauce.)
In a 9x13 baking dish place 1/2 cup of the mixture to coat the bottom of dish.
Lay out a cooked and cooled lasagna noodle on work surface. Sprinkle mozzarella cheese down the center of noodle. Place approximately 2 TBS of cubed cooked chicken on top of cheese. Roll the lasagna noodle up and place seam side down into baking dish. Once all lasagna noodles are rolled and placed into baking dish, pour remaining sauce over the lasagna rollups.
Sprinkle 1 cup of mozzarella cheese over sauce.
Bake for 30 minutes until cheese is golden and sauce is bubbly and hot.
