Cook the carrots. Heat about a tablespoon olive oil over medium heat. Sauté onion until translucent. Add cumin, ground coriander, and chili powder if using. Add carrots and cook over medium heat until carrots are softened about 8 minutes. Remove from heat and add salt, pepper, and lime juice to taste.
Assemble the enchiladas. Heat broth (or oil if using) in a small skillet over medium heat. Keep burner on low to keep broth hot. Add 1 tortilla to the skillet and cook until just pliable, about 20 seconds. Using tongs, transfer the tortilla to a clean work surface. Fill with about 3 tablespoons carrot mixture, and top with crumbled feta if desired. Roll carefully and place seam side down in a 9×13 or 9x9 casserole dish. Repeat with remaining tortillas and carrot mixture.
Bake enchiladas. Pour salsa verde over enchiladas and bake at 350F for 20 minutes. Garnish with feta and cilantro.
For the salsa verde: Broil the jalapeño and garlic. Place chile and garlic on a baking sheet or in a cast iron skillet. Roast under broiler about 4 minutes, watching carefully.
Transfer to blender. Puree with cilantro. Season with salt to taste.