Vulkan support multi-engine, but not how D3D12 does. The difference is that this feature is integrated in D3D12, so even if the hardware don't support asynchronous compute, the OS will manage everything to execute the code efficiently, without any direct support from the driver. On Vulkan this is not possible, so the driver will fully manage the execution. Technically the asynchronous compute is an OS level feature in D3D12, and a driver level feature in Vulkan.
NVIDIA support asynchronous compute in Vulkan. Check the queue section of the Vulkan database:
Pascal:
https://vulkan.gpuinfo.org/displayreport.php?id=1991
GCN(3):
https://vulkan.gpuinfo.org/displayreport.php?id=1995
You need to have three "Queue family". One with all the four flags (this will be the main engine), and two others. One with COMPUTE_BIT and one with TRANSFER_BIT. It doesn't matter if there are other flags in there. These will just allow better control.