To make the guacamole, place the avocado, cilantro, sour cream, chili powder, salt, and pepper in a food processor and pulse until smooth..
Mix chicken, canned chiles, jalapeno pepper, green onions, oregano, salt, garlic powder, and pepper in a bowl. Form the mixture into 4 patties.
Preheat an outdoor grill for medium heat.
Lightly oil the grill grate. Grill each patty 5 minutes per side, until well done. Move the patties to a cooler area of the grill to keep warm, and top each patty with a slice of Cheddar cheese. Lightly grill the buns while the cheese is melting.
Spread the bottom of each bun with guacamole, and top with 1/4 cup of shredded lettuce and a grilled chicken burger. Spoon 1 tablespoon of salsa on each burger and top with the other half of the bun to serve.