WWE at present holds five NXT TakeOver events per year but that number could be increased to six in 2020, according to WrestleVotes.
In 2019, WWE held NXT TakeOver specials attached to their big four; Royal Rumble, WrestleMania, SummerSlam, and Survivor Series PPVs in addition to a standalone TakeOver in June.
The decision to add another will no doubt hinge on the ratings for NXT on USA Network. However, WrestleVotes also notes that the current schedule makes it rather hard to add another.
A source states adding a 6th TakeOver event is a real possibility in 2020, all dependent on how the USA Network numbers look. The current TakeOver schedule of Jan, Mania weekend, June, Aug & Nov makes finding a slot for a 6th show a bit difficult.— WrestleVotes (@WrestleVotes) August 23, 2019