Will we know the nom the night of Saturday?
No. Counting the ballots will take a few days.
I do wonder if they'll release results on each round of the Ranked Choice Voting. That would be an interesting way to build suspense and interest.
Interesting RCV 5D chess instead of just letting people vote (especially Jewish people that can't vote due to religious reasons).
A convention always requires a majority of the delegates. Typically they would just spend all day at a convention hall instead of doing the ranked choice thing, but this is impossible nowadays.
For all the talk of them doing this specifically to block Amanda Chase, it's a longstanding thing for the VA GOP. About half of the State Central Committee is ideologically opposed to primaries because someone could win with less than half of the vote, and because it would be a open to non-Republicans. Therefore they feel that a primary could never properly represent the will of the Republican Party.