This is probably an easy fix, but I keep getting this error 'Attempt to compare number to nil' when obviously i'm NOT comparing anything to 'nil'.

local module = {}

function module:abbreviate(numz)
	local num = tonumber(numz)
	if num >= 1 and num <= 999 then
		return "$"..tostring(num)
	end
end

return module

other script:

module = require(Settings)
game.Players.PlayerAdded:connect(function(plr)
	local leaderstats = Instance.new("Folder", plr)
	leaderstats.Name = 'leaderstats'
	local rm = Instance.new("NumberValue", game.Lighting.MoneyStorage)
	rm.Name = plr.Name
	rm.Value = 0	
	local money = Instance.new("StringValue", leaderstats)
	money.Name = "Cash"
	money.Value = "$"..tostring(rm.Value)
	
	rm.Changed:connect(function()
		local mtp = rm.Value
		local mon = module.abbreviate(mtp)
		money.Value = mon
	end)
end)