Bring a large pot of salted water to a boil and cook the penne according to package directions until al dente; drain and set aside.
Meanwhile, heat 2 tsp olive oil in a large skillet over medium heat.
Season the chicken breasts with salt and pepper on both sides, then cook in the skillet 3–4 minutes per side, until cooked through and internal temperature reaches 165°F (74°C); transfer to a plate.
Spread 1 tsp prepared basil pesto over the top of each cooked chicken breast, then loosely cover with foil to keep warm.
In the same skillet, add the butter and garlic and cook briefly, stirring to loosen any browned bits from the pan.
Add the cubed cream cheese and whisk until mostly melted, then reduce heat to medium-low.
Gradually whisk in the heavy cream, continuing to whisk until the sauce is smooth.
Stir in the grated Parmesan, 1/4 tsp salt, 1/4 tsp pepper, and the drained julienned sun-dried tomatoes; whisk until the cheese is melted and the sauce is smooth.
Add the drained penne directly to the skillet and toss or stir to coat the pasta evenly with the Alfredo sauce.
Serve the sauced penne with the pesto-topped chicken breasts alongside and enjoy immediately.