A nested tuplet is when you have a tuplet beam (e.g. indicating a triplet) which is further subdivided into multiple tuplets (e.g. 2 groups of 8th notes followed by a triplet)
You can add nested tuplets to a PolyNome Playlist from the Add Items menu.
Say you want to enter a bar of 4/4 where the first note is a regular quarter note, and the last 3 notes are written as a nested tuplet of 5 : 3.
In PolyNome you need to split this bar into two playlist items. A bar of 1/4 for the first part, and a nested tuplet of 5 in the space of 3 quarters for the second part.
Watch the video below to see how it works