Pat the chicken breast dry and season both sides with chili powder, cumin, sea salt, and black pepper.
Heat the avocado oil in a medium skillet over medium-high heat until shimmering.
Place the chicken in the skillet and sear for 5 to 7 minutes per side until the exterior is golden and the internal temperature reaches 165 degrees Fahrenheit.
Remove the chicken from the pan and let it rest on a cutting board for 3 minutes before slicing into thin strips.
In a large salad bowl, combine the chopped romaine lettuce, halved cherry tomatoes, and finely diced red onion.
In a small ramekin, whisk together the Greek yogurt and lime juice to create a smooth, tangy dressing.
Arrange the sliced chicken and avocado over the greens, then sprinkle with pumpkin seeds for crunch.
Drizzle the lime-yogurt dressing over the top and garnish with freshly chopped cilantro.