Preheat oven to 400 degrees F (205 C). Saute onions for about 5-7 minutes in a small spray of non-stick spray. Add garlic, cook for 1 minute. In a large bowl, combine tomato sauce, chili powder, cumin, oregano, allspice, salt, pepper, hot sauce, agave nectar, garlic, onion, and beans and stir to mix well.
Lightly oil an 8x12-inch baking dish. Pour half of mixture into baking dish and tip back and forth to distribute evenly. Place half of tortillas on top of mixture (use 2 whole tortillas and cut a third to cover spots, or cut them all into strips). Place avocado slices on top of tortillas and season with a pinch of salt. Distribute corn kernels over avocado, then drizzle with lime juice. Top this layer with remaining tortillas, spread with remaining sauce, and sprinkle with crushed tortilla chips, then cheese.
Cover with foil and bake for 20 minutes, then uncover and bake another 7-10 minutes, until the cheese is melted and the casserole is bubbling at edges. Remove from over and sprinkle with cilantro.