Only moving on X plane, like a side-scroller or Mortal Kombat?
The basic way would be using a MoveTo node, which requires it has an AI Controller (probably does) and there be a NavMesh bounds. If actor is the target I believe it will move to where the actor is even if they move.
If the target actor is in a straight line from it, along X, it will only move in a straight line to it. Beyond that, it depends what you’re trying to do.
But I was assuming the actor is a pawn. A basic actor, maybe a MoveComponentTo node on the root component.
Or you could try an Finterp to, updating actor’s X location.