In a large pot or Dutch oven, combine the broken spaghetti, chicken broth, salt, garlic powder, and onion powder; bring to a boil over high heat.
Reduce heat to medium and simmer, stirring occasionally, until the spaghetti is al dente and most of the liquid is absorbed, about 12–15 minutes.
Stir in the shredded rotisserie chicken and undrained Rotel tomatoes until heated through.
Add the softened cream cheese and shredded Mexican cheese, stirring until cheeses melt and form a creamy sauce; adjust salt and pepper to taste.
Serve immediately, garnished with chopped cilantro or parsley if desired.
