More than 1,000 already sold in a few months and 5,000 to be sold in all of 2019.
According to the latest news, Hyundai sold so far this year (as of May 17, 2019) 1,075 Nexo (767 in South Korea and 308 abroad).
For comparison, sales in 2018 were 949 (727 in South Korea and 222 abroad). Sales of the Hyundai Tucson Fuel Cell (aka ix35 Fuel Cell) stand at 966, but that's over six years since 2013.
As we can see, the progress of FCV finally is relatively high on a year-over-year basis. The latest milestone was achieved mostly thanks to record April sales of several hundred Nexo, including 363 in South Korea.
Because the government is supporting hydrogen fuel cell cars in South Korea, Hyundai hopes to sell around 5,000 Nexo this year. However, abroad (outside of South Korea) we don't see such a movement.