Remove and discard skin and bones from chicken breasts.
Cut chicken breasts into strips, and set aside.
Melt 3 tablespoons butter in a large nonstick skillet over medium heat; add mushrooms and onion, and saut 6 minutes.
Add garlic, and saut 2 minutes.
Remove mushroom mixture from skillet.
Melt 2 tablespoons butter in the same skillet over medium heat; add chicken strips, and cook 10 minutes or until chicken is tender. Stir in wine, and cook 5 minutes. Return mushroom mixture to skillet, stirring well.
Remove skillet from heat.
Melt remaining 4 tablespoons butter in a small saucepan.
Whisk in flour until blended and smooth. Gradually whisk in milk, and cook, whisking constantly, 5 minutes or until mixture thickens. Stir in artichokes and next 3 ingredients.
Spoon chicken mixture into an 11- x 7-inch baking dish; top evenly with the artichoke mixture.