If one has 0 (zero) income but some assets (including cash), how much in assets limits one from being eligible for Medicaid?

Depending on marital status.
If single with no dependents-Most states limit cash and other assets to less than $2000. Homes with equity below limit set by your state.

Please please remember that for Medicaid they must show to be “at need” both financially and medically for the program they are applying to. For NH it’s need for skilled nursing care with solid documentation, like from a hospitalization. Just being old, iffy on their ADLs, not able to live alone, requiring medication management will likely not be enough to show “need”.