In a medium mixing bowl, combine the shredded chicken, cumin, chili powder, garlic powder, and salt.
Lay tortillas flat on a clean surface. Spread 2 tablespoons of refried beans in the center of each.
Distribute the chicken mixture and shredded cheese evenly over the beans.
Fold the left and right sides of the tortilla toward the center, then roll tightly from the bottom to create a sealed rectangular packet. Secure the seam with a toothpick if necessary.
Heat the vegetable oil in a deep skillet or Dutch oven to 375 degrees Fahrenheit (190 degrees Celsius).
Carefully place the chimichangas into the hot oil, seam-side down. Fry for 2 to 3 minutes per side until the exterior is golden brown and crispy.
Transfer the chimichangas to a wire rack or paper towel-lined plate to drain excess oil.
Prepare the guacamole by mashing the avocado flesh with lime juice and diced red onion in a small bowl until the desired consistency is reached.
Serve the chimichangas immediately, topped with a dollop of sour cream, the fresh guacamole, and chopped cilantro.