As noted in the Roadmap for the upcoming release 5.3, UE will support Nanite on all macbooks with at least a M2 chip. Most likely the M1 is missing due to the 64-bit atomics restriction!
But luckily this is a huge leap forward enabling the Macbooks to portable, efficient game development and gaming machines!
See more details here:
Support for Nanite on Apple M2 Devices - Unreal Engine Public Roadmap | Product Roadmap (productboard.com)