Preheat your grill to medium-high heat. In a small bowl, mix together garlic powder, onion powder, smoked paprika, salt, and pepper. Rub the spice mixture onto both sides of the chicken breasts.
Drizzle olive oil over the seasoned chicken breasts and place them on the grill. Cook for about 6-7 minutes on each side or until the internal temperature reaches 165°F. Remove from the grill and let rest for 5 minutes before slicing.
In a large salad bowl, combine the mixed greens, blueberries, feta cheese, sliced almonds, and red onion.
Slice the grilled chicken and arrange it on top of the salad. Drizzle with balsamic vinaigrette and toss gently to combine.
Serve immediately and enjoy your fresh and vibrant salad!