In a large pot or Dutch oven, combine the broken spaghetti, chicken broth, salt, garlic powder, and onion powder.
Bring the mixture to a boil over high heat, then reduce to medium and simmer, stirring occasionally, for 12–15 minutes or until the pasta is al dente and most of the liquid has been absorbed.
Stir in the shredded rotisserie chicken and the undrained can of Rotel tomatoes.
Add the softened cream cheese and shredded Mexican cheese; stir until the cheeses melt and form a creamy sauce.
Taste and adjust seasoning with additional salt and pepper if desired.
Serve immediately, garnished with chopped cilantro or parsley if using; the pasta will be thick, so eat right away.
Notes
Use pre-shredded or leftover rotisserie chicken for convenience.
If the sauce is too thick, thin with extra chicken broth to reach desired consistency.
Do not overcook the pasta; check for al dente at the lower end of the time range.
Softening the cream cheese first helps it melt more evenly into the sauce.