Attempt to index local 'player' (a nil value)?

A character isn't going to be the only thing that is added to the Workspace. An easy way to fix this is to add an if statement that checks to see if the character is actually a character.

game.Workspace.ChildAdded:connect(function(char)
	if game.Players:GetPlayerFromCharacter(char) then
		local player = game.Players:GetPlayerFromCharacter(char)
		local stats = player.leaderstats
		local spawn = game.Workspace:FindFirstChild(stats.Level.Value)
		char.Torso.CFrame = char.Torso.CFrame + Vector3.new(0,3,0)
		wait()
		char.Torso.CFrame = spawn.CFrame + Vector3.new(0,3,0)
	end
end)

`