node_panic.py

import bpy

def get_largest_area():
    window_reference = None
    surface_area = 0
    ctx = None
    for window in bpy.context.window_manager.windows:
        for area in window.screen.areas:
            w, h = area.width, area.height 
            surface = w * h
            if surface > surface_area:
                surface_area = surface
                window_reference = area
                override = bpy.context.copy()
                override['area'] = area

    return window_reference, surface_area, override


class OpenNodeEditor(bpy.types.Operator):
    """Open the node editor"""
    bl_idname = "scene.open_node_editor"
    bl_label = "Open Node Editor"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        area, size, ctx = get_largest_area()
        bpy.ops.screen.area_split(ctx, direction='HORIZONTAL',factor=0.5)
        bpy.ops.wm.context_set_string(ctx, data_path="area.type", value="NODE_EDITOR")

        return {'FINISHED'}


class LayoutDemoPanel(bpy.types.Panel):
    """Creates a Panel in the scene context of the properties editor"""
    bl_label = "Layout Demo"
    bl_idname = "SCENE_PT_layout"
    bl_space_type = 'PROPERTIES'
    bl_region_type = 'WINDOW'
    bl_context = "scene"

    def draw(self, context):
        layout = self.layout
        scene = context.scene
        row = layout.row()
        row.operator("scene.open_node_editor")


def register():
    bpy.utils.register_class(OpenNodeEditor)
    bpy.utils.register_class(LayoutDemoPanel)


def unregister():
    bpy.utils.unregister_class(LayoutDemoPanel)
    bpy.utils.unregister_class(OpenNodeEditor)


if __name__ == "__main__":
    register()