Preheat a grill pan or outdoor grill over medium-high heat.
Pat the chicken tenders dry and season both sides with salt and black pepper.
Drizzle the chicken with olive oil and coat evenly.
Grill for 3–4 minutes per side, or until the internal temperature reaches 165°F (74°C).
Transfer the chicken to a cutting board and let it rest for 5 minutes before slicing.
While the chicken cooks, whisk together the yogurt, chopped chives, garlic, olive oil, sea salt, and black pepper until smooth and creamy.
Arrange the chopped romaine lettuce on a large serving platter or individual bowls.
Neatly arrange the sliced chicken, hard-boiled eggs, cherry tomatoes, cucumber, avocado, and red onion over the lettuce.
Sprinkle the crumbled blue cheese evenly across the top.
Drizzle the homemade ranch dressing over the Chicken Cobb Salad or serve it on the side.
Garnish with additional chopped chives and serve immediately