The vitest globals seem to be sourced from here:

https://github.com/vitest-dev/eslint-plugin-vitest/blob/35ae43111e3d612e3cf59e10d8a95cfbb0e21791/src/index.ts#L281-L298

Comparing that to the eslint plugin I use, I notice the chai global is missing above:

https://github.com/saqqdy/eslint-plugin-vitest-globals/blob/d3fe9b63bfd7ae3751e2d6feb4a901208ad213b6/index.js#L14-L37

It definitely exists as of vitest@3.0.5.

This is likely a upstream bug in eslint-plugin-vitest, after that is fixed, the globals need to be regenerated.