Preheat the oven to 400F and line a baking sheet with parchment paper or a Silpat. Cut the spaghetti squash in half, scoop out and discard the seeds in the center, and place the squash halves face-down on the lined baking sheet. Bake for 45 minutes, or until the skin can be easily pierced with a fork. Remove from the oven and set aside to cool slightly.
In the meantime, pour the entire can of roasted tomatoes and green chiles (including the liquid) into a blender and add in the ground cumin and salt. Blend until smooth and set aside.
Melt the coconut oil in a large pot over medium heat and saute the onion until it's tender, about 8 minutes. Add in the garlic and spinach, and stir until the spinach is wilted. Use a fork to scrape the cooked spaghetti squash flesh into pot and pour the enchilada sauce over the top. Stir well until everything is heated through, season to taste, and then divide the cooked vegetables between the two shells of the spaghetti squash arranged cut-side-up on a baking sheet. (Alternatively, you can just use two oven-safe serving dishes, if you'd prefer.) Top each serving with shredded goat cheddar, and place the baking sheet under your oven's broiler, set to high, for about 3 minutes, or until the cheese is melted and bubbly. Serve warm.