WWE didn’t have NXT Superstars participate in the Survivor Series event because they wanted to keep the brands separated. This is the same reason why RAW Underground was nixed as well. It seems that Vince McMahon has strayed away from that idea.
The Lucha House Party are now on NXT, and they are also on RAW. It was noted in the Wrestling Observer Newsletter that Vince McMahon changed his mind about keeping Superstars on separate brands away from each other.
Vince evidently had a change of thoughts about it, because obviously there is no great business reason to put the Lucha House Party on NXT.
This change for WWE could happen during a perfect moment. The Royal Rumble is coming up, an event which usually sees all three WWE brands compete in the big battle royal matches. We’ll have to see if NXT joins the main roster for the Royal Rumble once again. The idea seems very likely at this point given the Lucha House Party’s arrival in NXT.