What is the cause of this and how to fix this nitro 5

Hai @Miggy01
Try with the basic steps of power drain and bios default by the following steps.
Power drain:
Unplug the charger cable from laptop.
On back of laptop there will be a pinhole.
Insert paper clip into the pinhole and press and hold for 30 seconds, then plugin the charger cable.

Bios default:
Keep on tapping F2 button after turning on computer immediately.
After getting the setup utility screen, tap on F9 and give yes to load default configuration.
Then, tap on F10 and enter to save and exit and computer will restart.

If these steps didn't work, try reinstalling the display driver:
1.Press and hold win+R to get run box
2.Type devmgmt.msc in the run box and click ok
3.In device manager, double click display adapter>intel graphics HD
4.Right click on it and uninstall device(Note: Make sure that the checkbox on delete the driver software for the device is unchecked)
5.Restart the computer and the display driver will be reinstalled.
These steps will work with display issues
Click accept if useful.