Currently the only movement script for 2D is AILerp. It is intended for games where you want the agent to follow the path exactly, which may sometimes not give perfectly smooth movement. There are a few experimental scripts (including an old version of the AILerp script) in this thread: 2D Pathfinding Top Down
[EDIT] In version 4 of the package the built in movement scripts work in 2D worlds as well. Take a look at https://arongranberg.com/astar/docs/pathfinding-2d.php