I'd need to think about it deeply, but at a first sight, nanoblogging would be a simple text (like the original twtxt spec, aimed for TUIs), and microblogging (like Twitter was a few years ago), would be about sharing texts, images, videos, GIFs, links, and perhaps Markdown styling.

Why? You have shorter messages than in a blog, but you may add almost anything you could do in a blog. Buuut... who knows?

well (insert stubborn emoji here) 😛, word blog comes from weblog, and microblogging could derivate from 'smaller weblog'. https://www.wikiwand.com/en/articles/Microblogging

I'd differentiate it from sharing status updates as it was done with 'finger' or even a BBS. For example, being able to reply; create new threads and sharing them on a URL is something we could expect from 'Twitter', the most popular microbloging model (citation needed)

I like to discuss it, since conversations usually are improved if we sync on what we understand for the same words.

it seems to be "an informational website consisting of discrete, often informal diary-style text entries (posts)" https://en.wikipedia.org/wiki/Blog and https://en.wikipedia.org/wiki/Blog#History