Season the chicken breast evenly with garlic powder, dried oregano, half of the sea salt, and half of the black pepper.
Preheat a grill or grill pan over medium-high heat and lightly coat with a small amount of oil if needed to prevent sticking.
Grill the chicken for 5-7 minutes per side until the internal temperature reaches 165°F and the outside is nicely charred.
While the chicken rests, halve the cherry tomatoes and dice the cucumber and avocado into bite-sized pieces.
In a small bowl, whisk together the olive oil, lime juice, and the remaining salt and pepper to create the dressing.
Place the mixed greens in a large bowl, add the tomatoes, cucumber, and avocado, then drizzle with the lime dressing and toss gently.
Slice the grilled chicken into strips and serve immediately over the fresh salad for a clean and satisfying meal.