Preheat grill or grill pan to medium-high heat.
Pat chicken dry and season with olive oil, garlic powder, paprika, salt, and pepper.
In a bowl, whisk together mayonnaise, Dijon mustard, honey, apple cider vinegar, olive oil, salt, and pepper.
Lightly oil the grill grates and place chicken on the grill.
Cook for 5–7 minutes per side until internal temperature reaches 165°F.
Remove chicken and let it rest for 5 minutes, then slice.
In a large bowl, combine greens, tomatoes, cucumber, onion, and avocado.
Add sliced chicken on top.
Drizzle with honey mustard dressing or toss lightly.
Serve immediately.