In a large mixing bowl, combine the ground chicken, corn kernels, breadcrumbs, diced red bell pepper, green onions, garlic powder, cumin, salt, black pepper, and cilantro.
Add the beaten egg to the mixture and mix everything together until well combined. You can use your hands for better mixing.
Preheat a grill pan or outdoor grill over medium heat and lightly coat with olive oil.
Divide the mixture into equal portions and shape them into burger patties (about 1/2 inch thick).
Carefully place the patties on the grill and cook for about 5-6 minutes on each side, or until fully cooked through (internal temperature reaches 165°F).
During the last minute of grilling, lightly toast the buns on the grill to give them a warm and crisp texture.
Assemble the burgers by placing a lettuce leaf and a slice of tomato on the bottom half of the bun, followed by the cooked chicken corn patty, and top with avocado slices if desired.
Place the top half of the bun on the burger and serve immediately with your favorite sides.