The Time Nodes
Editing time in Nuke is as easy as cutting bread with a stick of celery (well almost as easy). Nuke is simply not a time editor. However, though troublesome to implement, most of the standerd time edits are still possible.
There are a few nodes that, although they are not strictly time nodes, are nonetheless very much part of the time edit toolbox. Read
There are also aspects of the interface that are directly related to timing.
Also see: Script_Evaluation#Animation