01 - In a mixing bowl, combine shredded chicken with chili powder, cumin, garlic powder, salt, and lime juice. Mix thoroughly to coat the chicken evenly, then set aside to marinate briefly.
02 - Warm the refried beans in a small saucepan over low heat, stirring occasionally, until smooth and spreadable.
03 - Place the tostada shells on a serving platter. Spread a thin, even layer of the warm refried beans onto each shell using a spoon or spatula.
04 - Top each bean-covered shell with a portion of the seasoned shredded chicken. Layer with shredded lettuce, diced tomatoes, diced red onion, and shredded cheese.
05 - Add a dollop of sour cream, followed by fresh cilantro, jalapeño slices, and avocado slices.
06 - Serve immediately with lime wedges on the side for squeezing over the top.