a nil value?

so im making a small tycoon and instead of using on touch bricks like most im using a GUI button system (i hope) so ive got a tycoon kit and am trying to convert the ontouch brick into a clickable GUI button, im pretty bad at lua so idk what im doing.

the problem with my button is in the output it says attempting to call a nil value (hit) on line 16,

i dont know how to fix this, i want this to work as a button to buy the part like in a tycoon

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model = workspace.Tycoon.Factory.Part2
Upgradecost = 0
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upgradeStuff = model:clone()

wait(1)

model:remove()
owner = workspace.Tycoon.Factory.OwnerName 
local ting = 0

function Click(hit)
    if ting == 0 then
    ting = 1
    check = hit.Parent:FindFirstChild("Humanoid")

    if check ~= nil then
    if hit.Parent.Name == owner.Value then
        local user = game.Players:GetPlayerFromCharacter(hit.Parent)
        local stats = user:findFirstChild("leaderstats")

        if stats ~= nil then
            local cash = stats:findFirstChild("Gold")
            if cash.Value > (Upgradecost-1) then

                cash.Value = cash.Value - Upgradecost
                upgradeStuff.Parent = script.Parent.Parent.Parent
                script.Parent:remove()

            end
        end
    end
    end

    ting = 0
    end
end

script.Parent.MouseButton1Click:connect(Click)