Heat oven to 400°F. In a glass bowl, blend refried beans and chiles. Cover; microwave on HIGH for 1 minute.
Stir together ricotta, egg, Mexican seasoning and salt; set aside.
Spread 1/2 cup of the enchilada sauce evenly in a 13 x 9-inch baking pan. Overlap 6 corn tortillas to create a layer. Spread half each of the black bean mixture and ricotta mixture evenly over tortillas. Top with half of the Mexicorn, half the chicken and 1 cup shredded cheese. Top with 1/2 cup enchilada sauce.
Add 6 more tortillas; top with 1/4 cup enchilada sauce. Repeat layering the black bean mixture, ricotta mixture, Mexicorn, chicken and 1 cup shredded cheese. Top with 1/2 cup enchilada sauce and last 6 tortillas. Spread with remaining enchilada sauce; sprinkle with remaining 1 cup shredded cheese.
Cover with foil; bake at 400°F for 40 to 45 minutes or until bubbly. Let rest 5 minutes before serving.