Bring first 3 ingredients to a boil in a large saucepan; gradually whisk in cornmeal. Cook 4 minutes or until thickened and bubbly, stirring constantly. Remove from heat; stir in Parmesan cheese. Spoon polenta evenly into 2 (8") square disposable ovenproof pans (see Note below). Cool 10 minutes.
Sprinkle artichoke hearts, peppers, and chicken evenly over polenta. Pour Alfredo sauce over chicken in both pans. Sprinkle with basil; top with Italian cheese blend. Cover and chill until ready to bake.
Before baking, place pan on center of a baking sheet. Bake, uncovered, at 350° for 25 minutes or until casserole is thoroughly heated.
Note: We tested with Glad OvenWare disposable pans. Clip and save instructions from back or bottom panel, and share these instructions when gift giving.