Step 1

Preheat oven to 350°F.

Step 2

Heat oil in a large ovenproof skillet, such as cast-iron. Add corn, green and red peppers, and onion; cook, stirring occasionally, until charred, 7 to 10 minutes. Gradually add spinach in batches; cook, stirring frequently, until wilted, 1 to 2 minutes.

Step 3

Stir in chicken, enchilada sauce, and salsa until combined. Gently stir in tortilla strips. Sprinkle with cheese. Transfer to the oven and bake until bubbly, about 15 minutes.

Step 4

Top the casserole with tomatoes, cilantro, and radishes.