Preheat oven to 400 degrees F (204 degrees C)
Peel and cut squash into bite-size pieces. Rub with 2 tablespoons of the olive oil and season with salt and pepper. Place on a lined baking sheet.
When oven is hot, bake the squash. Set timer for 45 minutes.
While the squash bakes, prep the mushrooms: rinse dry, and quarter them. Place on a lined baking sheet. Drizzle and toss with 2 tablespoons of the olive oil and season with salt and pepper.
When 30 minutes remain on the timer, put the mushrooms in the oven with the squash.
In a blender, combine almond milk, cashews, nutritional yeast, and 1/2 teaspoon salt. Blend until smooth. Pour mixture into a bowl. Clean and dry the blender for the next sauce.
Heat the remaining 2 tablespoons of olive oil over medium heat. Add the garlic and onion. Saute for 3 minutes, stirring occasionally. Add cumin, oregano, and salt. Saute 3 more minutes, stirring occasionally.
Add garlic-onion mixture to the blender, together with roasted chile peppers and vegetable stock. Pulse until blended coarsely. This step can also be done in a food processor.
Place spinach in a microwave-safe bowl. Cover bowl with plastic wrap. Microwave for 20-30 seconds until spinach leaves are just wilted. Remove spinach from bowl and dry with a paper towel.
Wrap tortillas snugly in a damp paper towel and place on a plate. Heat in microwave for 30 seconds or until tortillas are warm and pliable.
When timer sounds, check on squash and mushrooms. If fully cooked and tender, remove them from the oven. If not, bake 5 more minutes and check again.
Assemble the enchiladas in the baking dish:
Spread a thin layer of green chile sauce on the bottom of the dish.
Place a warm tortilla on a plate and scoop a few pieces each of mushrooms, squash, and spinach (there should be enough to fill the tortilla when rolled up).
Drizzle a generous amount of the cashew cream sauce onto the ingredients in the tortilla.
Taking care not to let any of the contents spill out, pick up and roll up the tortilla and place it in the baking dish as shown in the picture above.
Repeat the assembly steps for the rest of the tortillas.
Moisten the tortilla flaps with a bit of water if they don't stay wrapped tightly.
Spread another thin layer of green chile sauce on top of the assembled enchiladas.
Sprinkle plant-based cheese on top, if using.
Cover baking dish and bake for 15 minutes. Remove cover and bake 5 more minutes, or until heated through and tortilla edges are slightly crispy.
Squeeze lime juice over enchiladas and garnish with cilantro before serving.