Wiktionary
next up
n. That which is next; the next to be up.
Usage examples of "next up".
If the others were on plan, Cord would be the next up, then Despreaux.
Even should he decide to take the next up train from Dover he still had a yawning hour to fill.
I next up-edge the small slates and place a rubber band around them placing them in the sitter's lap.