Prep the ingredients per the instructions above.

Preheat a grill or griddle pan over medium heat.

In a bowl, whisk together the garlic powder, dried oregano, lemon juice, and olive oil to make the marinade. Season with salt and pepper to taste. Adjust until the marinade is well-balanced. Reserve half of the marinade to use for brushing the buns.

Brush one side of the butterflied chicken breast with the marinade and season with additional salt and pepper.

Place the marinated side of the chicken on the hot grill or pan. Brush the top with more marinade. Cook for about 6 minutes until grill marks appear.

Flip the chicken and brush with the remaining marinade. Cover the pan or close the grill and cook for another 6 minutes, or until the chicken reaches an internal temperature of 165°F (74°C). Remove from heat and let rest for 5 minutes.

Brush the insides of the brioche buns with the reserved marinade. Toast or grill until golden brown and set aside.

To assemble the sandwich, spread mayonnaise on both bun halves. Layer with butter lettuce, tomato slices, the grilled chicken, Swiss cheese, and sliced red onion.

Prepare the chia fresca: combine all the ingredients together. Stir well and let sit for 5 minutes to allow the chia seeds to bloom.

Serve the grilled chicken sandwiches with carrot sticks, hummus, fresh blueberries, and chia fresca.