Slice chicken breasts into 1/2-inch strips. Place strips in a bowl and pour buttermilk over them; stir to coat. Let sit 15 minutes at room temperature or up to 1 hour refrigerated.

Heat oil

Pour vegetable oil into a 10-inch skillet to a depth of about 1/2 inch (or heat a fryer to 350°F / 175°C). Heat over medium-high until shimmering and a pinch of flour sizzles on contact.

Make coating

In a shallow bowl combine flour, cornstarch, 1 teaspoon salt, 1/2 teaspoon black pepper, paprika, garlic powder, and onion powder. Mix thoroughly.

Coat and fry

Remove chicken strips from buttermilk, letting excess drip off. Dredge strips in the flour mixture, pressing to adhere. Fry in batches without crowding, 3–4 minutes per side, until golden brown and internal temperature reaches 165°F (74°C). Transfer to a paper towel-lined tray to drain and rest 3 minutes, then slice into bite-size strips if desired.

Dressing

Whisk together mayonnaise, sour cream (or Greek yogurt), lime juice, honey, cumin, chili powder, 1/4 teaspoon salt and 1/4 teaspoon black pepper in a small bowl. Add 1 tablespoon water to loosen to a pourable consistency. Taste and adjust seasoning or lime.

Salad assembly

In a large bowl, combine mixed salad greens, diced tomato (or 1 cup chopped), sliced black olives, corn, shredded cheddar, chopped red onion and chopped cilantro.

Toss the salad lightly with about half the dressing to coat (reserve extra dressing for serving). Arrange salad on individual plates or a large platter.

Top the dressed greens with hot fried chicken strips and scatter tortilla strips over the top so they remain crisp.

Garnish with sliced avocado and lime wedges. Serve immediately with remaining dressing on the side.