Heat a large skillet over medium-high heat. Add olive oil and let it shimmer before adding the frozen vegetables. Stir occasionally, allowing them to thaw and begin to brown slightly, about 5-7 minutes.

Add diced cooked chicken to the skillet, stirring to combine with the vegetables. Cook for an additional 3-4 minutes, allowing the chicken to heat through and the flavors to meld.

Evenly sprinkle garlic powder, onion powder, and dried thyme over the skillet contents. Stir thoroughly to ensure the vegetables and chicken are well-coated. As the spices heat, they will release a warm, inviting aroma. Continue stirring for about 2 minutes, allowing the flavors to meld and the fragrance to develop fully.

Sprinkle salt and freshly ground black pepper over the skillet, stirring gently to combine. Taste the mixture, adjusting the seasoning if necessary to achieve your desired balance. Ensure the vegetables are evenly coated and the flavors are well-integrated, providing a harmonious taste throughout the dish.

Continue cooking over medium heat until the vegetables reach a tender-crisp texture and the chicken is thoroughly heated. Listen for a gentle sizzle, which indicates moisture is evaporating and the ingredients are cooking evenly. Stir occasionally to prevent sticking and ensure even cooking throughout the skillet.

Once the vegetables and chicken are cooked through and have a slight golden hue, remove the skillet from the heat. Drizzle with freshly squeezed lemon juice, ensuring even coverage. This citrus touch enhances the overall aroma and balances the savory flavors, providing a refreshing contrast to the dish.

Sprinkle grated parmesan cheese evenly over the skillet's contents. Cover the skillet with a lid for about two minutes, allowing the cheese to soften and meld with the vegetables and chicken. The cheese should become slightly gooey, enhancing the overall texture and providing a subtle, savory finish.

Gently stir the mixture over medium heat for about 2 minutes, ensuring the lemon juice is evenly distributed. This helps the cheese melt smoothly, coating the vegetables and chicken. Watch for a slight sheen on the surface, indicating the ingredients are well combined and ready to serve.

Transfer the skillet mixture to a serving dish while still hot, ensuring the colors remain vibrant and appealing. The enticing aroma will fill the room, creating a welcoming atmosphere. Serve immediately to maintain the ideal temperature and texture, allowing everyone to enjoy the meal at its best.

Sprinkle additional black pepper over the skillet to enhance the aroma and add a subtle kick. This step not only boosts the dish's visual appeal with a speckled finish but also complements the existing flavors. Serve immediately to enjoy the warm, inviting aroma and the vibrant colors of the vegetables.