Below are some functions that may be used. Please try it out.
nrf_gpio_port_out_set() or nrf_gpio_port_out_clear()
See the file below for details.
C:\Users\xxxx\AppData\Local\Arduino15\packages\Seeeduino\hardware\mbed\2.9.2\cores\arduino\mbed\targets\TARGET_NORDIC\TARGET_NRF5x\TARGET_SDK_15_0\modules\nrfx\hal\nrf_gpio.h
See also the following sections of the datasheet
6.9.2 Registers