Preheat oven to 375F. Spray a 9-inch x 13-inch casserole dish with non-stick spray.
Heat 3 tbsp oil in large pan sauté sweet potato on medium/low until tender (about 15-20 minutes). In separate pan, heat 1 tbsp oil and saute onion and red pepper for about 5 minutes. Mix in the half jar of corn salsa, spices, salt and pepper to taste, and finely chopped jalapeño. Add in drained beans and sweet potato.
Wrap a dozen corn tortillas in a moist paper towel and microwave for 1 minute to soften. Repeat again with the other 12 tortillas.
Shred the chicken into bite-sized pieces; set aside.
Layer 6 tortillas into the bottom of the casserole dish, arranging them so the whole surface is covered as much as you can. Over that make a layer of the vegetable mixture, 1/3 of the chicken, and 1/3 of the cheese. Drizzle with green enchilada sauce. Repeat the process 2 more times, ending with the rest of the sauce and cheese on top.
Bake uncovered until the casserole is bubbling and cheese is melted and browning on top, about 40 minutes. Let sit about 5 minutes before serving hot.
Serve with sour cream, tomatoes, chopped cilantro, and a wedge of lime.