Preheat oven to 375 degrees then coat a 9" x 13" baking dish with cooking spray.
Place chicken into baking dish. Salt and pepper chicken and then bake for 15 minutes.
Place defrosted spinach and artichokes into a colander and press very firmly to squeeze out as much liquid as possible. Transfer veggies to a cutting board, chop coarsely then add to a medium bowl.
Add remaining ingredients to the bowl and stir to combine. Pour on top of chicken and bake 20–25 minutes.
Let stand about 5 minutes before serving.
Notes
We cut the chicken into 1" cubes, but you can make them bigger or smaller to fit your preference!