It was recently revealed that NXT on USA would be airing on Tuesday for the next two weeks due to the NHL Playoffs taking their timeslot on Wednesday nights. Later it broke that the Syfy channel would be airing those episodes on Wednesday anyway, the first time the yellow-and-black brand has aired on that channel since 2010.
According to the Wrestling Observer, NXT is running these encores on Syfy so AEW isn’t running without competition when they air in their normal Wednesday timeslot on TNT. AEW recently aired on Saturday and Thursday due to the NBA playoffs, but they released their 2019 ALL OUT pay per view on their company Youtube channel on Wednesdays so NXT would not be running without competition either.
Both programs will return to their normal Wednesday slot in a few weeks.