Attempting to find occupants name of A-Chassis vehicle

I am attempting to put a players unit number on a license plate of a vehicle, the value of the players unit number is located in ServerScriptService under a couple of folders.

I have tried to locate the driveseat and get the occupant of the driveseat, but it seems to give me an error.

Here is my script:

local characterValues = game.ServerScriptService.GameManager.CharacterScripts.ESCharacterValues
local player = script.Parent.Parent.Parent.Parent.Parent.Parent.DriveSeat.Occupant.Parent
local character = characterValues:FindFirstChild(player.Name)

local plate = character.UnitNumber.Value


			
for i,v in pairs(script.Parent.Plates:GetChildren()) do
	v.SGUI.Identifier.Text = plate
end

Here is the error:

Workspace.Model.DPS-1-3.Body.Model.License Plates.LicensePlate.Plate.LicensePlateGenerator:4: attempt to index nil with 'Parent' 

Strange, the error link to line 4 in the script you provided is a blank line.
Are you sure that
local player = script.Parent.Parent.Parent.Parent.Parent.Parent.DriveSeat.Occupant.Parent
has the right amount of Parents?
The error states that one of the Parents is nil, so you may have to look at the hierarchy again.
Maybe post a screenshot of the Explorer window, with this script and the DriveSeat showing.