Yes, I can do it.
However, I'd love to use this opportunity to also add namespace translations, because it's done in the same file. It's very simple! Read the "Translating namespace names" section on this page: Translating:MediaWiki#Translating namespace names. I only need translations for the words in the "Namespace name" column in the first table (but please read the explanations in the "Description" column before translating to make sure you understand them correctly).
Thank you. I admit I am not a native speaker, though I can mostly understand the language.
The following translations are those that I believe are appropriate:
Media - Media Special - Especial MediaWiki - MediaWiki Template - Plantilla Help - Ayuda Category - Categoria
The rest I am not entirely certain as I am not a native speaker.
Is it still possible to switch?
It's possible, but can you please involve native speakers? Configuration changes of this kind are a major thing, especially for a language that already has a Wikipedia with an active community of editors. They may be difficult to undo if someone doesn't like it. For example, can you start a discussion about this on a community discussion page in the Chavacano Wikipedia and get some responses? Thanks for understanding :)