Add all spices (oregano through pepper) in a medium-size bowl. Add jalapenos, then ground chicken. Mix thoroughly until all spices and jalapenos are mixed throughout. Form into 3 or 4 even patties. Set aside until ready to grill.
Spray a grill pan with cooking spray, and heat grill until hot.
Spray both sides of the chicken with cooking spray. Add the chicken burgers and sear/cook for 5 minutes on high. Flip and cook for another 5 minutes. Check doneness of chicken with a meat thermometer to ensure it's done and safe to eat.
Add the cheddar cheese and cook until melted, roughly 1 minute. Remove chicken patties from grill and set aside, and let rest 3-5 minutes.
Add buns to top rack and grill until you achieve desired grill marks. Remove buns from grill.
Assemble burgers by placing smashed avocado, onion, tomato and burgers on bottom bun. Top with aioli, and serve. Top with remaining diced jalapenos, if desired.