Cook spaghetti noodles according to package directions to al dente, drain, and set aside.
Preheat oven to 350 degrees F and prepare a 9x13 inch casserole dish by spraying it with non-stick spray.
Heat 2 tablespoons olive oil in a large skillet over medium high heat. Add onions and diced red bell peppers and sauté until the vegetables are tender.
Add in 1 can Rotel (drained) and stir to combine.
To the pan, stir in cream of mushroom soup, cream cheese, chicken broth, milk, dried oregano, dried basil, garlic powder, salt, and black pepper. Stir to combine.
Stir in cooked spaghetti noodles and cooked shredded chicken. Then stir in cheddar cheese. Mix well.
Pour the chicken spaghetti mixture into the prepared baking dish. Top with 1 cup mozzarella cheese.
Bake for 25-30 minutes or until cheese is melted and bubbly.
Garnish with chopped green onions or chopped fresh parsley.