Preheat oven to 400°F.
Peel and chop sweet potato into ½" pieces. Spread onto a baking sheet, drizzle with 1 tbsp olive oil, season with salt and pepper and toss with your hands to make sure each piece is coated.
Roast sweet potatoes for 20-25 minutes, stirring and tossing potatoes every 10 minutes to ensure even cooking. Potatoes are done when they can be easily poked with a knife or a fork.
Meanwhile, prep the rest of the veggies. Chop onion, mince garlic, slice mushrooms, and chop cilantro.
Heat a large skillet. Once heated add 1 tbsp olive oil and the chopped yellow onion. Once onion starts to soften, add garlic, mushrooms and oregano, cumin, salt and paprika. Once mushrooms have cooked down, add spinach, corn, and cilantro. Cook just until spinach is wilted and remove pan from heat.
Once the potatoes are done, add them to the skillet with the other veggies and stir to incorporate.
Heat tortillas by either wrapping in a damp paper towel and microwaving in 30 second increments, or heat on a dry skillet on the stovetop, or by lighly frying in oil in a pan on stovetop.
Once tortillas are heated, time to assemble. To each tortilla, add a few spoonfuls (¼-½ cup) of the filling and roll tortilla. Place seam-side down into a 9-13" baking dish.
Once all enchiladas are rolled, pour sauce over the top of all tortillas.
Bake enchiladas at 400°F for 15-20 minutes.
While enchiladas are baking, prepare cashew lime crema. Add all ingredients to a high speed blender and blend until smooth. Start with ½ cup water for thicker consistency, use more water for thinner consistecy. Taste to adjust for seasoning.
Once enchiladas are done baking, remove from oven and let cool slightly. Top with cashew lime crema, lettuce, tomato, and onion (optional) and serve!