How to Make It
reheat oven to 350º. In a large saucepan, heat 2 tablespoons of the olive oil. Cook the onion over moderate heat until soft and translucent, about 5 to 7 minutes. Add the garlic, jalapeño, chili powder, cumin, crushed red pepper, paprika, oregano, sugar, salt and pepper and cook, stirring, for 1 minute. Stir in the tomatoes and remove from heat. Blend in a food processor or blender until smooth. Return the tomato mixture to heat, and bring to a simmer. Add the chicken breasts and cook, stirring occasionally, until the chicken is no longer pink and cooked through, about 20 to 25 minutes.
Transfer the chicken to a cutting board and use two forks to shred it. Place the chicken in a large bowl and add the pineapple. Stir in 1 cup of the sauce.
Wrap the tortillas in a damp paper towel and warm them in a microwave oven until soft and pliable, about 1 minute.
Spread a thin layer of sauce on the bottom of a 9-by-13-inch glass baking dish. Arrange the tortillas on a work surface. Spoon the chicken mixture onto the tortillas. Roll up the tortillas and arrange in the baking dish. Top evenly with the remaining sauce. Sprinkle the top of the enchiladas with the cheese. Bake for 15 to 20 minutes, until the enchiladas are hot and the cheese is melted.
Serve warm with sour cream, jalapeños, lime wedges and minced green onions.