There're no specific threads regarding how to plot DNL/INL in the Cadence Virtuoso. Or am I able to export the data then achieve nonlinearity in Matlab>?
You could use VIVA calculator's dnl and inl expressions, in Cadence/Spectre user guide there are useful descriptions how to use the builtin functions. Browse for "virtuoso visualization and analysis xl user guide" on Cadence community forum.
Or click link below, this is an earlier version and only dnl expression is described in it: