Preheat the Oven: Set the oven to 400°F.
Cook the Filling: Heat a 12-inch ovenproof skillet over medium-high heat. Add the ground pork, using a wooden spoon to break it into small crumbles. Cook until only a small amount of pink remains, about 4 minutes. Mix in the garlic powder, chili powder, cumin, oregano, and salt. Continue stirring for another minute or two until the pork is fully cooked.
Incorporate Vegetables and Sauce: Tear the spinach into smaller pieces and stir it into the meat mixture. Pour in ¼ cup of the salsa verde and add the crushed pineapple. Cook for another 1 to 2 minutes, allowing the sauce to blend into the meat. Remove from heat.
Assemble the Enchiladas: Lay the tortillas flat on a clean surface. Place about ½ cup of the pork mixture in the center of each tortilla. Sprinkle approximately 2 tablespoons of shredded cheese on top. Roll the tortillas tightly and arrange them seam-side down in the same skillet used to cook the pork.
Bake the Enchiladas: Pour ½ cup of the remaining salsa verde into the skillet, spreading it evenly to coat the bottom. Arrange the filled tortillas in the pan, seam-side down. Pour the rest of the salsa verde over the top, then finish by sprinkling the remaining cheese over the enchiladas. Transfer to the oven and bake for about 15 minutes, or until the cheese is fully melted.
Serve and Enjoy: Top with your favorite garnishes, such as pickled onions, avocado slices, fresh cilantro, scallions, hot sauce, or sour cream. Serve warm.