This indicator plots the "expected move" of SPX for today's trading session. Expected move is the amount that SPX is predicted to increase or decrease from its current price, based on the current level of implied volatility. The implied volatility in this indicator is computed from the current value of the VIX (or one of several volatility symbols available on Trading view). The computation is done using standard formula. The resulting plots are labeled as 1 and 2 standard deviations. The default values are to use VIX as well as 252 trading days in the years.
Use the square root of (days to expiration, or in this case a fraction of the day remaining) divided but the square root of (252, or number of trading days in a year).
timeRemaining = math.sqrt(DTE) / math.sqrt(252)
Standard deviation move = SPX bar closing price * (VIX/100) * timeRemaining