Why is is saying attempt to index nil with Touched?

Here is my code

local model = workspace.Plots["1"].Building

model.ChildAdded:Connect(function()
    for name, child in pairs(model:GetChildren()) do
        child:FindFirstChild("Hitbox").Touched:Connect(function(hit)
            if hit.Parent ~= child then
                child:Destroy()
            end
        end)
    end
end)

The child is a model and it has a part under it called Hitbox but in the console it is saying attempt to index nil with Touched