Preheat oven to 375℉.
Heat a large pot of boiling water over medium-high heat.
Add 6 teaspoons Knorr Caldo de Tomate bouillon powder or chicken broth bouillon powder to water.
When water comes to a boil, add 16 oz spaghetti, broken in half
In a separate small skillet, add chopped green peppers and chopped onions and cook until translucent. (If shredded cooked chicken is cold, you might add the chicken to the skillet of veggies for a couple minutes just to heat through.)
Drain spaghetti in colander.
Transfer drained spaghetti to large mixing bowl.
Add peppers and onions, cream of mushroom soup, 3/4 of the shredded Velveeta cheese, olives, drained Rotel, shredded or chopped cooked chicken, and seasonings to bowl.
Stir well.
Pour into greased 9x11 baking pan. Top with the remaining 1/4 shredded Velveeta cheese.
Bake in oven for 15-20 minutes or until cheese is melted and casserole is heated through.