Start by cooking the chicken. In a large skillet over medium heat, add a generous drizzle of olive oil. Once hot, add the chicken breasts and season with salt and pepper. Cook for about 6-7 minutes on each side, or until fully cooked through. Remove from the skillet and allow to cool before shredding the chicken.
In the same skillet, add a bit more olive oil if needed, then toss in the sliced red onion and red pepper. Sauté for about 5 minutes until softened. Add the finely chopped onion and crushed garlic, cooking for another 2 minutes until fragrant.
Sprinkle in the cumin and dried oregano, stirring well to combine. Then, add the chopped chipotle in adobo sauce (or chili powder) and mix thoroughly, allowing the spices to toast for about a minute.
Pour in the chicken stock and tomato puree (or Italian passata), followed by the brown sugar. Stir to combine and let simmer for about 10 minutes, allowing the flavors to meld together. Taste and adjust seasoning with salt and pepper as necessary.
Preheat your oven to 180°C (350°F). In a large baking dish, spread a thin layer of the sauce on the bottom. Take a tortilla, fill it with shredded chicken and a spoonful of the veggie mixture, then roll it up and place seam-side down in the baking dish. Repeat with the remaining tortillas.
Once all the enchiladas are assembled, pour the remaining sauce over the top and sprinkle with both cheddar and mozzarella cheese. Bake in the preheated oven for 20-25 minutes, or until the cheese is bubbly and golden brown.
Remove from the oven and let cool for a few minutes before serving. Garnish with fresh herbs or avocado slices if desired, and enjoy your homemade Chipotle chicken enchiladas!
