As far as I can tell from the narrative, Venezuela was basically serving as a puppet state for China, and if that's true, I would probably give that as the primary reason, but who knows. Maybe it's because Venezuela did poorly in the FIFA World Cup qualifier and this was action dictated by his recent peace prize award.

On a slightly more serious note, the charges against Maduro were actually filed in 2020: https://www.justice.gov/archives/opa/pr/nicol-s-maduro-moros...