How do I get this to loop forever

It looks like you're working on an autofarm script for a game that involves teleporting to chests and picking them up. You're using the `:GetChildren` method to find all the chests with different names. However, you're encountering an error once all the chests have been picked up.

One potential issue is that the script doesn't stop when there are no more chests available, causing it to continue running and eventually causing an error. To fix this, you can add a check to stop the script when there are no more chests left to pick up.

Here's how you can modify your script:

```lua

ChestToggle:OnChanged(function()

    while Options.ChestFarm.Value == true do

        local ChestsAvailable = game:GetService("Workspace").chests:GetChildren()

        if #ChestsAvailable == 0 then

            -- No more chests available, so exit the loop

            break

        end

        for i = 1, #ChestsAvailable do

            if Options.ChestFarm.Value == true then

                local child = ChestsAvailable[i]

                if child == nil then return end

                local Chest = game:GetService("Workspace").chests:FindFirstChild(child.Name)

                local Prompt = Chest:WaitForChild("ProximityPrompt")   

                game.Players.LocalPlayer.Character.HumanoidRootPart.Position = Chest.Position

                wait(0.5)

                Prompt.HoldDuration = 0

                fireproximityprompt(Prompt, 1, 100)

            end

        end

    end

end)

```

In this modified version, the script checks if there are no more chests available (`#ChestsAvailable == 0`) and exits the loop if that's the case. This prevents the script from running into errors when there are no chests left to pick up.

Thanks for answering.