Saute chopped onions, peppers and garlic in olive oil, about 5 minutes over medium heat. Add mushrooms and continue to saute until mushrooms begin to soften, about 4 minutes more.
While the veggies are cooking, put pasta in a large pot of boiling water and cook until al dente. (still firm to the bite) WARNING: They will continue to cook and absorb the sauce in the oven, so do not overcook here. The package directions should give instructions for al dente cooking times, but for my penne, it's usually about 9 minutes. When they are finished, drain well and return to pan. Mix in ricotta and mozzerella cheeses.
When the veggies are softened, add the pasta sauce and stir well. Add the chicken and black olives.
Hopefully you really used a Large Pot for your pasta, because I find it easiest to mix everything in there before assembling. Add pasta/chicken mix to pasta/cheese mix and stir gently until well blended.
Pour all into shallow backing dish (a 9x13 will work, I use a similar sized oval baking dish). By keeping it shallow, you'll be sure to get a nice crust.
Sprinkle bread crumbs over top, followed by parmesan. I like to spray a little cooking spray on it to help give nice browning. (You could pour a little melted butter, but the Pam does the trick and saves calories to enjoy for the pasta!).
Place in preheated oven and bake, uncovered for 20-25 minutes, until bubbling and browned on top.
Let it sit a few minutes before serving (to allow the cheeses to firm a little and because it is TOO HOT to eat just out of the oven.