The point is, in countries such as Mexico, there was/is a trend to displace the identity of predominately indigenous peoples as mestizo. Thus, the erasure of peoples who while not entirely indigenous, are significantly more indigenous than European or African. My view is not that these countries are as if the Mesoamerican civilizational complex never ended, but to place more nuance on the view that everyone became mestizo and a new cultural identity was borne as a mixture, that is spoken of by Mexican national policy and even by other countries, such as Peru, Ecuador and others.
Regarding these states you asked me to mention, states that require more nuance to this question include,
Mexico
Bolivia
Peru
Ecuador
Guatemala
Honduras
El Salvador
Panama
Belize
Parts of Colombia
Parts of Venezuela
Parts of Argentina (north)
Parts of Chile, Mapuche lands in the north
For simplicity's sake I propose the "mestizo" identity could easily mean they are Indigenous, with or without mixed ascendance, with their cultural identity co-opted by "European" institutions, No one could argue that a Mexican,Peruvian, Guatemalan,Honduran, Salvadorean, Ecuadorian´s Mestizo don´t have a lot of Indigenous admixture in his blood,and that in these cases, with different socio-cultural dynamics in the build of their State-nations, I Argue that in the new world first come the State and they then build the Nation unlike in the old world, is possible they prefer to exalt their Indigenous past and disregard, officially, their European origin, and this is easier to do as in those lands historically thete were pretty advanced and powerful civilization were to extract their identity.(Aztec, Maya, Zapotec, Toltec, Tarascan, Inca).
The other countries mentioned have more difficult they don´t have a big indigenous population (Argentina ,Uruguay) or have relative speaking minor civilizations, (Colombia, Venezuela, Panamá) Chile as Ever is a strange case they have a big powerful native population, but relatively "minor" civilization with powerful and warlike empires, is strange