Begin by preparing the buffalo chicken. In a bowl, toss the chicken pieces with garlic powder, paprika, salt, and pepper.
Heat a skillet over medium heat and add the butter. Once melted, add the seasoned chicken pieces and cook until they are browned and fully cooked, about 7-8 minutes.
Reduce the heat to low and pour the buffalo sauce over the cooked chicken, stirring to coat evenly. Cook for an additional 2-3 minutes, then remove from heat and set aside.
While the chicken is cooling, prepare the salad by combining the mixed salad greens, diced celery, cucumber, red onion, cherry tomatoes, cheddar cheese, and blue cheese crumbles in a large bowl.
For the dressing, whisk together mayonnaise, sour cream, apple cider vinegar, Dijon mustard, garlic powder, salt, and pepper in a small bowl until smooth and creamy.
Drizzle the dressing over the salad and toss to coat evenly.
Divide the salad among four plates and top each with an even portion of the buffalo chicken.
Serve immediately, and enjoy your Spicy Buffalo Chicken Salad!