Looking at the Windows Hypervisor Platform headers it does appear to be possible.

There's the NestedVirtSupport bit of the WHV_PROCESSOR_FEATURES1  structure which is passed as the input buffer to WHvSetPartitionProperty with the WHvPartitionPropertyCodeProcessorFeaturesBanks property code. There's also the WHvPartitionPropertyCodeNestedVirtualization property which appears to take a BOOL as the input buffer to the function.

I'm not clear how these two approaches differ, or how one affects the other. The WHvPartitionPropertyCodeNestedVirtualization property feels the most promising. It's noted in the Data Types documentation for the function that NestedVirtualisation is supported since Windows 10 19H2.

This is from a very quick look at the API documentation and header files, so may not be 100% accurate, but overall appears promising.