Slice chicken breasts horizontally into thinner cutlets or pound to 1/2-inch thickness. Mix 1 tbsp olive oil, garlic powder, Italian seasoning, salt, and pepper together and rub over the chicken.

Heat a skillet over medium-high heat. Cook chicken for 4-6 minutes per side until internal temperature reaches 165°F (74°C). Let rest for 5 minutes, then slice into strips.

Slice ciabatta rolls in half. Brush the outer crusts of top and bottom halves liberally with the 3 tbsp of olive oil.

Spread pesto generously on the inside cut surfaces of all bread halves. On bottom halves, layer mozzarella, sliced chicken, tomatoes (seasoned with a pinch of salt), and another layer of mozzarella. Top with the other bread half.

Heat a skillet or panini press over medium heat. Cook sandwiches, pressing down with a weight if using a skillet, for 4-5 minutes per side until golden brown and cheese is fully melted.

Remove from heat, let cool for 1 minute, slice in half diagonally and serve hot.