Place the chicken breasts in a large freezer bag with two tablespoons of Italian dressing. Seal tightly and turn to coat evenly. Refrigerate for at least 30 minutes, turning once halfway through.

Place the Instant Pot® trivet inside the cooking container and arrange the marinated chicken breasts on top. Add the water and sprinkle with garlic powder, onion powder, salt, and pepper.

Secure the lid and set the valve to Sealing. Cook on Manual High Pressure for 8 minutes.

While the chicken cooks, prepare the tortellini according to the package directions. Add olive oil to the cooking water if directed on the package to help prevent sticking. Drain well and transfer to a large bowl.

Allow the Instant Pot® pressure to release naturally for 10 minutes, then carefully release any remaining pressure. Transfer the chicken to a cutting board and allow it to cool slightly.

Cut the chicken into one-inch cubes and add it to the bowl with the tortellini.

Add the olives, tomatoes, and two tablespoons of Italian dressing. Season lightly with salt and pepper and gently toss to combine.

Thread the ingredients onto the skewers. A suggested order is olive, tomato, chicken, tortellini, chicken, tortellini, tomato, olive.

Arrange the finished skewers on a serving platter. Serve with the remaining Italian dressing on the side for dipping.