Preheat your oven to 350°F (175°C). Season the chicken breasts with salt and pepper, then cook in a skillet for 6-7 minutes on each side until fully cooked. Shred the chicken once cooled.
In the same skillet, add the melted butter and sauté chopped onion, bell pepper, and portabello mushrooms over medium heat for 5-7 minutes.
In a mixing bowl, combine shredded chicken, sautéed vegetables, cream of chicken soup, and drained diced tomatoes. Mix well.
Lay out each tortilla and spoon the chicken mixture into the center. Sprinkle with cheese, fold the sides, and roll tightly. Place seam-side down in a baking dish.
Sprinkle remaining cheese on top, cover with aluminum foil, and bake for 15 minutes. Remove foil and bake for an additional 10 minutes until cheese is bubbly and golden.
Let the burritos cool for a few minutes before serving. Enjoy with your favorite toppings!
