Bring a large saucepan of water to a boil. Cook pasta according to package directions. Drain.

Sprinkle chicken with ⅛ teaspoon each salt and pepper. Heat oil in a large skillet over medium heat. Add the chicken and cook, turning once, until browned and an instant-read thermometer inserted into the thickest part registers 165°F. Transfer to a plate.

Combine spinach and water in a large saucepan. Cook over medium heat, stirring occasionally, until just wilted, about 2 minutes. Add cream cheese and milk to the pan; stir until the cream cheese is melted. Add Parmesan, garlic powder and the remaining ⅛ teaspoon each salt and pepper; cook, whisking, until thickened and bubbling. Add artichokes and the cooked pasta; toss to combine.

Divide the pasta mixture among 4 bowls. Thinly slice each chicken breast and arrange on top of the pasta. Sprinkle with additional Parmesan, if desired.