Slice the chicken breast into thin strips and toss in a small bowl with the cumin, garlic powder, sea salt, and black pepper.
Heat the olive oil in a large non-stick skillet over medium-high heat.
Add the sliced bell peppers and red onions to the skillet, sautéing for 3-4 minutes until they begin to soften and char slightly.
Push the vegetables to the side of the pan and add the seasoned chicken strips, cooking for 5-6 minutes until golden brown and cooked through.
Remove the chicken and vegetable mixture from the pan and set aside on a plate; wipe the skillet clean with a paper towel.
Place the tortilla in the warm skillet and sprinkle half of the shredded cheddar cheese over one half of the tortilla.
Layer the cooked chicken and sautéed vegetables over the cheese, then top with the remaining cheese.
Fold the tortilla in half to cover the filling and press down gently with a spatula.
Cook for 2-3 minutes per side until the tortilla is golden brown and crispy and the cheese is fully melted.
Slide the quesadilla onto a cutting board, let it rest for one minute, then slice into wedges and serve.