Preheat oven to 350 degrees.

Cut chicken into bite size pieces. In a large skillet melt butter over medium heat.  Add cubed chicken, garlic & onion powder. Cook over medium-high heat until chicken is no longer pink. *NOTE: Consider using rotisserie chicken instead to make preparation quicker.

Stir in soup, cubed Velveeta and Rotel diced tomatoes with green chilis. Reduce heat to low, and cook until the cheese melts, stirring constantly.

Stir in cooked spaghetti. Season with salt and pepper, to taste.

Pour into a lightly greased 2 quart casserole dish and bake for 30 minutes or until heated through.