Start by seasoning the chicken breasts with salt and pepper. Grill or pan-sear them until cooked through, about 6-8 minutes per side. Allow the chicken to rest for a few minutes before slicing it into strips.
While the chicken is cooking, prepare the hard-boiled eggs by placing them in a pot of water. Bring to a boil, then reduce the heat and let them simmer for 10 minutes. Once done, transfer the eggs to a bowl of ice water to cool before peeling and slicing.
Assemble the salad by arranging the spring mix lettuce in individual plates.
Top the lettuce with the sliced chicken, pepperoncini, sliced hard-boiled eggs, cucumber, grape tomatoes, and avocado chunks.
Drizzle our Lemon Vinaigrette desired dressing over the salad just before serving.
Garnish with additional salt and pepper, if desired.