Start by heating the butter or oil in a large skillet over medium heat. Add the chopped onion and red bell pepper, cooking for about 3-4 minutes until they begin to soften. Next, add the chopped zucchini (or yellow squash) and the thawed hashbrowns. Sprinkle in the ground cumin and garlic powder, stirring everything together. Cook for an additional 5-7 minutes or until the veggies are tender and fragrant.
While the vegetables are cooking, preheat your oven to 375°F (190°C). To make the tortillas more pliable, you can warm them in a dry skillet for a few seconds on each side or wrap them in a damp paper towel and microwave for about 30 seconds.
Spread a thin layer of enchilada sauce on the bottom of a 9x13 inch baking dish. Take a warmed tortilla, place a generous spoonful of the sautéed veggie mixture in the center, and sprinkle with cheese. Roll the tortilla tightly and place it seam-side down in the baking dish. Repeat this process until all tortillas are filled and arranged in the dish.
Once all the enchiladas are in the baking dish, pour the remaining enchilada sauce evenly over the top, ensuring each enchilada is well-coated. Sprinkle the shredded Mexican cheese blend generously over the sauce.
Cover the baking dish with aluminum foil (if desired) and bake in the preheated oven for 20 minutes. Then, remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly, and the edges of the tortillas are slightly crispy.
