As previously reported, Fox held a meeting last week with their affiliates to discuss the 2019 fall schedule. During the meeting, Fox confirmed that there are talks about moving NXT to one of their channels.
Dave Meltzer noted on the latest edition of Wrestling Observer Radio that WWE is "absolutely" planning to use main roster talent on the NXT show if they go head-to-head with AEW. One issue with NXT airing on Wednesday nights is that FS1 airs Big East College Basketball that night during their season.
In its current format, NXT has been airing on the WWE Network since 2014. There was a special airing of NXT on the USA Network as part of "WWE Week" in December of 2017, which averaged 841,000 viewers. RAW that week averaged 2.684 million viewers, while SmackDown pulled in 2.481 million, so NXT averaged less than a third of what the two flagship shows drew.
In addition to NXT possibly airing on FS1, a weekly WWE studio show will air on the network Tuesdays with Renee Young as the host.