Preheat your grill to medium-high heat, around 400°F (200°C). Coat the chicken with olive oil, then season with Italian seasoning, salt, and pepper. Grill for 5-6 minutes per side until cooked through (165°F/75°C). Let it rest before cutting into bite-sized pieces.

In a large pot, bring water to a boil and add salt. Cook rotini pasta according to package instructions for 8-10 minutes. Drain and rinse under cold water to halt the cooking process.

Combine Italian seasoning, olive oil, and Italian dressing in a bowl or jar. Whisk or shake until blended and let sit in the refrigerator for about 10 minutes.

In a large mixing bowl, combine cooled pasta, grilled chicken, cucumber, cherry tomatoes, red onion, olives, mozzarella, and parsley. Drizzle dressing over the top and toss until well-coated.

Serve immediately for freshness, or cover and refrigerate if preparing for later. Can be stored in an airtight container for up to 3 days.