Add VK_ICD_FILENAMES=/usr/share/vulkan/icd.d/nvidia_icd.json
If your using proton 5.13 - there’s some kind of regression that causes VK_ICD_FILENAMES and LID_LIBRARY_PATH to be overridden, so you have to temporarily delete (or move) the non nvidia configs in /usr/share/vulkan/icd.d.