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Nevada is a pretty poorly educated state so if education polarisation replaces racial polarisation that is terrible news for Democrats there, and its Democratic trend appears to have peaked a decade ago.
Another factor currently sustaining NV's D lean is the fact that a substantial share of its working class voters are unionized. In general, unionized working class voters are more Democratic than non-unionized working class voters; much of the Democrats' decline in working class support in other regions can be attributed to the decline of unionization in those areas. If union membership somehow declines there (similar to how it declined in the Rust Belt and/or Appalachia), then that could also tip the state to the Republicans.