Lay chicken thighs on a clean surface and cut to burger bun size. Mix the garlic powder, onion powder, paprika powder, coriander powder, and salt in a small bowl. Sprinkle over chicken on both sides and let sit in the fridge until needed.
Add flour and beaten egg to different bowls. Season flour with pinch of salt and Sonoran Spice Carolina Reaper powder, give a quick mix.
Preheat oil in a pan. Take out chicken thighs from the fridge. Coat chicken in flour mixture on both sides, tab to remove excess flour then dip in the egg until well coated, add chicken back to flour and remove the excess. Deep fry chicken for about 4 minutes per side or until golden brown.
Make spicy ranch by mixing the ranch dressing and a pinch of Sonoran Spice Carolina Reaper Powder together.
Assemble the sandwich by spreading the bottom buns with 1 tbsp of spicy ranch dressing, topped with fried chicken, onion, tomato, lettuce, and top bun. Enjoy with fries!