In a medium bowl, combine the ground chicken, sea salt, black pepper, garlic powder, and onion powder.
Gently form the mixture into one large, uniform patty, being careful not to overwork the meat to maintain a tender texture.
Heat the avocado oil in a non-stick skillet over medium heat until shimmering.
Place the chicken patty in the skillet and cook for 5 to 6 minutes per side, or until the internal temperature reaches 165°F.
While the chicken cooks, lightly toast the whole grain bun in a separate pan or toaster until golden brown.
Mash the avocado onto the bottom bun, then layer with the butter lettuce, tomato slices, and red onion.
Place the cooked chicken patty on top of the vegetables and finish with the top bun.