Creamy Chicken Tetrazzini Pasta Bake

12 ounces of spaghetti
2 cups cooked chicken, shredded
1 can (10.5 ounces) cream of mushroom soup
1 can (10.5 ounces) cream of chicken soup
1 cup sour cream
1 cup chicken broth
1/2 cup grated Parmesan cheese
1/2 cup shredded mozzarella cheese
1/4 cup butter
1 small onion, finely chopped
1 clove garlic, minced
1 cup sliced mushrooms
1 cup frozen peas
Salt and pepper to taste
1 tablespoon dried Italian seasoning
1/2 cup breadcrumbs