On PCPartPicker, it says that these two are not compatible. However, I have seen builds where something similar is attained. What would prevent this from being functional? It is within the length restraints of the case.
The Gigabyte is 70mm thick and the NR200 only supports 60mm. Case only supports 156mm including the power cable, the Gigabyte is 150mm and you are going to need more than 6mm for the cable. If you want a 4090 get the MSI Ventus, it is 62mm but I have seen people put them in the NR200.