Heat 1 tablespoon avocado oil in large oven-safe skillet over medium-high heat.
Add ½ cup diced red onion. Cook 6 minutes, stirring occasionally, until softened.
Add 3 cloves minced garlic, 1 diced red bell pepper, and 1 small diced zucchini. Cook 4-5 minutes, stirring, until crisp-tender.
Stir in 1½ teaspoons chili powder, 1 teaspoon ground cumin, ½ teaspoon smoked paprika, ½ teaspoon garlic powder, and ½ teaspoon red chili flakes. Cook 30 seconds, until fragrant. Season with salt and pepper.
Add 3 cups shredded rotisserie chicken, 15 ounces rinsed and drained black beans, and 1 cup frozen fire-roasted corn. Pour in half the enchilada sauce and stir to combine.
Pour in remaining enchilada sauce.
Stir in ¼ cup cilantro and ½ cup shredded cheese. Taste and adjust seasoning.
Gently fold in 6 cut corn tortillas until fully coated in sauce.
Reduce heat to medium-low. Cover with lid and cook 8-9 minutes.
Remove lid. Stir gently. Sprinkle remaining 1 cup cheese evenly over top.
Set oven to broil on high. Place skillet under broiler 3-4 minutes until cheese is melted, golden, and bubbly. Watch closely.
Top with sliced green onions, remaining ¼ cup cilantro, sliced avocado, dollops of sour cream or Greek yogurt, sliced jalapeño if using, and lime wedges. Serve straight from skillet.