Pat the chicken breasts dry with paper towels to remove excess moisture, which helps achieve a good sear.
Place the chicken on a cutting board and use a sharp chef’s knife to cut into 1-inch cubes, ensuring each piece is roughly the same size for even cooking.
Transfer the cubes to a mixing bowl and season generously with salt, pepper, and garlic powder. Toss to coat evenly, allowing the flavors to meld for about 10 minutes.
Heat a skillet over medium-high heat until shimmering, then add the olive oil. Swirl to coat the pan evenly.
Once the oil is hot and starts to shimmer, add the chicken cubes in a single layer. Let them sear undisturbed for 2-3 minutes until they develop a golden-brown crust.
Use tongs to flip the cubes, then cook for another 2-3 minutes until they are evenly browned and opaque in the center.
Check that the internal temperature reaches 75°C (165°F) or the chicken is no longer pink in the center. Remove from heat and squeeze lemon juice over the cubes for a bright finish.
Optionally, sprinkle with chopped fresh herbs like parsley or thyme for added aroma and color. Serve immediately for juicy, tender, and beautifully browned chicken cubes.