Cook the rigatoni according to package instructions. Drain and set aside.

Heat a large skillet over medium-high heat and add a drizzle of olive oil.

Season the cubed chicken well with salt and pepper, then add it to the skillet and cook until browned and nearly cooked through.

Add the chopped shallots and garlic to the skillet and cook for 3 minutes, stirring often and being careful not to let the garlic burn.

Lower the heat to medium-low and stir in the chopped sun-dried tomatoes, fresh spinach, half and half, Dijon mustard, and Italian dressing. Stir until the spinach wilts and the sauce is combined.

Add the drained pasta to the skillet and toss everything together until well coated.

Serve warm.