Preheat oven to 400.
In a large skillet** over medium heat, melt butter and saute onion until translucent.
Add Spinach, artichokes and jalapeno.
Saute until spinach is wilted.
Sprinkle with a little salt and pepper.
In large bowl, mix cream cheese, mayo, sour cream and garlic powder until smooth.
Add mixture to skillet.
Add cooked cubed chicken and mozzarella to skillet.
Stir.
Pour contents into baking dish (like an 8×8 pan), if not using an oven safe skillet.
Top with parmesan and bake for 20 minutes or until bubbly and brown.