Preheat oven to 425°F. Grease a non-stick cookie sheet using cooking spray. Heat 1 tbsp of oil over medium-high heat in a large skillet with high sides.
Season raw, uncooked diced chicken with salt, pepper and 1 tbsp of taco seasoning.
When oil is hot, brown the chicken on all sides for 5-7 minutes. When chicken is fully browned, add in onion, peppers, and garlic. Cook until onions and peppers are just softened, approximately 4-5 minutes. Season with salt and pepper and remaining taco seasoning, stirring to coat all ingredients.
Add in the butter chicken sauce and stir until all ingredients are fully coated in sauce. Simmer for 5 minutes.
While the sauce is simmering, prep your tortillas by brushing one side with oil (this step is optional if you are deciding to use cooking spray.)
After the chicken and sauce mixture has finished simmering, fill each tortilla with a heaping spoonful of the filling. Roll the flautas up ensuring that they are placed seam side down on the greased cookie sheet.
When all 8 flautas are rolled up, spray with cooking spray. (This step is optional if you already brushed the outsides of the tortillas with oil.)
Place flautas in the oven and bake until browned and crispy, approximately 8-12 minutes. Check on them frequently to ensure they aren't burnt.
While the flautas are baking, make the pico de gallo by simply combining all pico de gallo ingredients in a small bowl. (Optional)
When flautas finish baking, top with any toppings of your choice and serve immediately.