If you were using a Control-based node, I'd say the HBoxContainer node is what you'd need. For Node2D-based nodes, the HBoxContainer won't work though, and I don't think there is anything built in that would handle it. That said, you can always program your own solution.
For example, something like this (untested):
extends Node2D
export (float) var separation_distance = 24
func _ready():
arrange_nodes()
# For this example, we'll just sort all of the children nodes.
# Additionally, we'll place the Node2D nodes starting at this
# node's position, and expand from there on the horizontal axis.
func arrange_nodes():
# some children may not be Node2D-based, so we don't want to
# move them or account for their position.
var position_index = 0
for child_node in get_children():
if child_node is Node2D: # if it extends Node2D...
# position the node and increase the position index so
# the next node is offset correctly.
child_node.position = Vector2(position_index * separation_distance, 0)
position_index += 1
else:
continue
