Add the chicken to a 9 x 13” baking dish in a single layer ( a slight overlap is fine) and lightly season with salt and pepper.
In a medium size bowl, stir together the cream cheese, salsa and fajita seasoning packet and spread the mixture evenly over the top of the chicken.
Sprinkle half of the cheese on top and add the sliced peppers and onions. Lightly season with salt and pepper then top with the rest of the cheese.
Place it into the center rack of the oven for 30 minutes or until the chicken is cooked all the way through. Let it rest for 5 minutes, garnish with parsley (optional) and serve in a warm tortilla.