Hmmm at this short time frame, using 252 (trading days) vs 365 days (calendar time as in Black Scholes etc.) can make a difference in calculating daily vol. Far as I can tell most gurus use 252 but it's debated. But you're asking about overnight (17.5 hours). So, overnight IV = Price * .16 * sqrt((17.5/24)/252) ... maybe Just taking a stab at it. Wonder when they'll start offering hourly expiration?

Yes. Basically I’m asking if it’s possible to derive overnight implied volatility if given one year implied volatility? If not, if one year Implied vol is 16, how do we find the expected daily movement of the underlying? Is it... 16 * sqrt(1/365) = 0.837 ?

IMO, the formula was not meant to do that, but others might have more knowledge. The formula was meant to only use the days the market is open. About 252.