Prepare spicy mayo by mixing mayonnaise and sriracha sauce with a whisk. Set aside.
Bacon
Preheat oven to 400 F. Prepare a cookie sheet, lined with parchment paper, add bacon and bake for 10 minutes. Once done, set aside
Caramelized Onions
Preheat a large nonstick skillet over medium heat. Add 1 tablespoon of olive oil and add onions to the skillet. Start sautéing the onions on medium heat, stirring occasionally, until onions begin to soften and brown, about 10 minutes. Increase the heat to medium-high, add a splash of water to the pan and continue cooking the onions for 5 more minutes. Remove onions from the skillet.
Chicken burgers patties
Mix chili powder, salt, cumin, minced garlic, and black pepper together in a small bowl. Add egg and whisk slightly. Add ground chicken.
Gently form the chicken into 4 balls, then lightly press into 4-inch-wide, ½-inch thick patties (or 1-inch for thicker patties). Set aside.
Reheat the skillet on medium hot and add olive oil. Add burgers and cook until browned on each side, 5 minutes per side. Turn off the heat, add cheese on top of the hot patties and set aside.
Assembly
Assemble the burger: bottom bun, layer of spicy mayo, lettuce, tomato, chicken burger patty with cheese, more spicy mayo, if desired. And finally, add the bacon, completing the assembly with the top bun.