Cook pasta in salted boiling water according to package instructions, until al dente. Drain and set aside.
Heat 1 tablespoon of olive oil in a large skillet, then add sliced onion and sauté over medium heat until softened.
Roughly chop the sun-dried tomatoes and add them to the skillet; sauté with onions for about 1 minute.
Add the cooked chicken (shredded or diced) and heat through for 2-3 minutes.
In a medium bowl, combine cream cheese with milk, garlic powder, salt and pepper. Use a fork or a small whisk to stir the sauce until smooth, then add it to the pan with the chicken.
Toss in the cooked pasta, the remaining olive oil, and stir in Parmesan cheese.
Serve warm with a sprinkle of Parmesan cheese and a drizzle of olive oil on top.