Pat chicken breasts dry with paper towels and season uniformly with salt, black pepper, garlic powder, and dried oregano.
Heat olive oil in a large heavy-bottomed or oven-safe skillet over medium-high heat.
Add chicken breasts to the skillet and sear for 6-7 minutes on the first side until a golden-brown crust forms.
Flip the chicken and cook for another 5 minutes, or until the internal temperature reaches 160°F (71°C).
Place one slice of mozzarella and two tomato slices on top of each chicken breast.
Cover the skillet with a lid for 2 minutes to melt the cheese and allow the chicken to reach the target internal temperature of 165°F (74°C).
Remove from heat and spread 1 tablespoon of basil pesto over the melted cheese on each breast.
Drizzle with balsamic glaze and garnish with fresh basil chiffonade before service.