In a bowl, marinate the chicken tenderloins in buttermilk for at least 30 minutes in the refrigerator.
Preheat the air fryer to 400°F.
In a separate bowl, mix the flour, garlic powder, onion powder, paprika, salt, and pepper.
Remove the chicken from the buttermilk and dredge each piece in the flour mixture, ensuring an even coating.
Place the coated chicken tenders in the air fryer basket in a single layer. Spray lightly with cooking spray.
Air fry for 10-12 minutes, flipping halfway through, until the chicken is golden brown and cooked through.
While the chicken is cooking, prepare the salad by combining the mixed greens, cherry tomatoes, cucumber, avocado, shredded cheddar cheese, and red onion in a large bowl.
Once the chicken is done, slice it and add it to the salad. Drizzle with honey mustard dressing and toss gently to combine.