• Preheat oven to 375 degrees. Coat a 9 x 13-inch baking dish with cooking spray. Set aside.

Prepare enchilada filling:

• Heat olive oil over medium-high in a large frying pan.
• Saute onion, stirring often, until it begins to brown around the edges (about 5 minutes).
• Add zucchini and corn kernels to pan, then cook until zucchini begins to soften, stirring frequently.
• Reduce heat to medium and let pan cool slightly.
  
• Stir black beans into vegetables and cook until heated through.
• Add garlic, cumin, oregano, and salt to pan and cook until fragrant (about 1 minute), stirring constantly.
• Remove pan from heat and season to taste with additional salt, if desired. Set aside.

Make crema verde:

• Place salsa and sour cream in a medium bowl. Whisk until combined.

Assemble enchiladas:

• Cover the bottom of the baking dish with a layer of crema verde.
• Wrap 4 tortillas in a paper towel or dish cloth. Heat tortillas in microwave for 45 seconds or until very hot.
• Carefully remove 1 tortilla and place it on a flat surface (keep the remaining tortillas covered so they don't dry out).
• On one end of the tortilla, place 1/12 of the vegetable filling. Roll up the tortilla tightly and place it in the baking dish.
• Repeat this process with the remaining 3 tortillas and then heat 4 more tortillas and repeat again.
• After all the tortillas are filled, cover them with the remaining crema verde.
• Top the enchiladas with the cheddar cheese, then bake until heated through and cheese is melted, about 25 to 30 minutes.
• Remove from oven and serve immediately. Enjoy!