Prep the oven. Preheat your oven to 400°F. This ensures that your taquitos will bake evenly from the start.
Lightly brush. Grab a 9×13-inch baking dish and lightly brush it with the melted butter. This prevents the taquitos from sticking and adds flavor.
Cook the chicken. In a large skillet, melt 1 tablespoon of butter over medium heat. Add the cut chicken breasts and sprinkle half the fajita seasoning over it. Stir to coat evenly. Cook for about 5 minutes until the chicken is no longer pink and has a slight char. Remove from the skillet and set aside.
Cook the veggies. In the same skillet, add the remaining 2 tablespoons of butter. Once melted, toss in the sliced onions and bell peppers. Sprinkle the remaining fajita seasoning over the top and sauté for a few minutes until the vegetables are tender and the onions are translucent.
Assemble the taquitos. On a cutting board, lay a tortilla flat. Place a generous spoonful of the chicken and vegetable mixture followed by a couple tablespoons of shredded cheese on top. Roll it tightly and place it seam-side down in the baking dish. Repeat with the remaining tortillas.
Brush with butter. Once all taquitos are assembled, brush the tops with melted butter for a nice golden finish.
Bake. Place the baking dish in the preheated oven and bake for about 15 minutes or until the tortillas are golden and crispy. If they’re not browning, you can turn the broiler on for 1 to 2 minutes, keeping a close eye to avoid burning.
Ready to serve. Remove from the oven and let cool for a couple of minutes. Serve your Baked Chicken Fajita Taquitos with salsa and/or sour cream for dipping.
