Preheat oven to 350°. Spray a shallow 3-quart baking dish with cooking spray.
In a large skillet, heat oil over medium-high heat. Add onion; cook until lightly browned, about 4 minutes. Add spinach; cook, stirring frequently, until wilted, about 2 minutes. Remove from heat. Stir in beans, corn, chiles, cilantro, lime juice, garlic powder, and cumin.
Spread 1 teaspoon cream cheese onto each tortilla. Cut 3 tortillas in half. Place 4 whole tortillas, cream cheese side up, in prepared dish. Fill in any spaces with 2 tortilla halves. Spread half of bean mixture over tortillas. Sprinkle with 1 cup Monterey Jack. Repeat layers once. Top with remaining tortillas. Spread salsa over top. Loosely cover with foil.
Bake until heated through, about 35 minutes. Spread sour cream over top, and sprinkle with remaining 1 cup Monterey Jack. Bake, uncovered, until cheese is melted, about 5 minutes more. Garnish with cilantro, radish, and lime slices, if desired.
Notes
Kitchen Tip: When covering a casserole with foil, spray the underside with cooking spray to prevent sticking.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/bean-corn-enchilada-casserole-recipe/